Browsers(firefox/chromium) lagging after a few mins of video playback

For some reason on trying to playback videos on youtube. the cpu usage shoots up over 70% and causes the entire system to lag, however on opening the same video with mpv it stays ~1% which means that vaapi is working correctly on mpv but not for firefox and chrom(ium)
for firefox and chrom(ium) I followed both their steps to enable video decoding ( gfx.webrender.all to true and media.ffmpeg.vaapi.enabled to true in about:config for firefox, and the following flags for chromium: NixOS/system-config/packages.nix · master · drishal / dotfiles · GitLab)
both of them reported hardware video decoding but still CPU usage is insanely high.
Any other tips on what can I do?
some info:

vainfo
~ ❯ vainfo
Trying display: wayland
libva info: VA-API version 1.18.0
libva info: Trying to open /run/opengl-driver/lib/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_18
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.18 (libva 2.18.2)
vainfo: Driver version: Mesa Gallium driver 23.1.1 for AMD Radeon Graphics (renoir, LLVM 15.0.7, DRM 3.52, 6.3.8)
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            :	VAEntrypointVLD
      VAProfileMPEG2Main              :	VAEntrypointVLD
      VAProfileVC1Simple              :	VAEntrypointVLD
      VAProfileVC1Main                :	VAEntrypointVLD
      VAProfileVC1Advanced            :	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointEncSlice
      VAProfileH264Main               :	VAEntrypointVLD
      VAProfileH264Main               :	VAEntrypointEncSlice
      VAProfileH264High               :	VAEntrypointVLD
      VAProfileH264High               :	VAEntrypointEncSlice
      VAProfileHEVCMain               :	VAEntrypointVLD
      VAProfileHEVCMain               :	VAEntrypointEncSlice
      VAProfileHEVCMain10             :	VAEntrypointVLD
      VAProfileHEVCMain10             :	VAEntrypointEncSlice
      VAProfileJPEGBaseline           :	VAEntrypointVLD
      VAProfileVP9Profile0            :	VAEntrypointVLD
      VAProfileVP9Profile2            :	VAEntrypointVLD
      VAProfileNone                   :	VAEntrypointVideoProc
vdpauinfo
display: :0   screen: 0
API version: 1
Information string: G3DVL VDPAU Driver Shared Library version 1.0

Video surface:

name   width height types
-------------------------------------------
420    16384 16384  NV12 YV12 
422    16384 16384  UYVY YUYV 
444    16384 16384  Y8U8V8A8 V8U8Y8A8 
420_16 16384 16384  
422_16 16384 16384  
444_16 16384 16384  

Decoder capabilities:

name                        level macbs width height
----------------------------------------------------
MPEG1                           0 65536  4096  4096
MPEG2_SIMPLE                    3 65536  4096  4096
MPEG2_MAIN                      3 65536  4096  4096
H264_BASELINE                  52 65536  4096  4096
H264_MAIN                      52 65536  4096  4096
H264_HIGH                      52 65536  4096  4096
VC1_SIMPLE                      1 65536  4096  4096
VC1_MAIN                        2 65536  4096  4096
VC1_ADVANCED                    4 65536  4096  4096
MPEG4_PART2_SP                  3 65536  4096  4096
MPEG4_PART2_ASP                 5 65536  4096  4096
DIVX4_QMOBILE                  --- not supported ---
DIVX4_MOBILE                   --- not supported ---
DIVX4_HOME_THEATER             --- not supported ---
DIVX4_HD_1080P                 --- not supported ---
DIVX5_QMOBILE                  --- not supported ---
DIVX5_MOBILE                   --- not supported ---
DIVX5_HOME_THEATER             --- not supported ---
DIVX5_HD_1080P                 --- not supported ---
H264_CONSTRAINED_BASELINE       0 65536  4096  4096
H264_EXTENDED                  --- not supported ---
H264_PROGRESSIVE_HIGH          --- not supported ---
H264_CONSTRAINED_HIGH          --- not supported ---
H264_HIGH_444_PREDICTIVE       --- not supported ---
VP9_PROFILE_0                  --- not supported ---
VP9_PROFILE_1                  --- not supported ---
VP9_PROFILE_2                  --- not supported ---
VP9_PROFILE_3                  --- not supported ---
HEVC_MAIN                      186 139264  8192  4352
HEVC_MAIN_10                   186 139264  8192  4352
HEVC_MAIN_STILL                --- not supported ---
HEVC_MAIN_12                   --- not supported ---
HEVC_MAIN_444                  --- not supported ---
HEVC_MAIN_444_10               --- not supported ---
HEVC_MAIN_444_12               --- not supported ---
AV1_MAIN                       --- not supported ---
AV1_HIGH                       --- not supported ---
AV1_PROFESSIONAL               --- not supported ---

Output surface:

name              width height nat types
----------------------------------------------------
B8G8R8A8         16384 16384    y  NV12 YV12 UYVY YUYV Y8U8V8A8 V8U8Y8A8 P010 P016 I8A8 
R8G8B8A8         16384 16384    y  NV12 YV12 UYVY YUYV Y8U8V8A8 V8U8Y8A8 P010 P016 I8A8 
R10G10B10A2      16384 16384    y  NV12 YV12 UYVY YUYV Y8U8V8A8 V8U8Y8A8 P010 P016 I8A8 
B10G10R10A2      16384 16384    y  NV12 YV12 UYVY YUYV Y8U8V8A8 V8U8Y8A8 P010 P016 I8A8 

Bitmap surface:

name              width height
------------------------------
B8G8R8A8         16384 16384
R8G8B8A8         16384 16384
R10G10B10A2      16384 16384
B10G10R10A2      16384 16384
A8               16384 16384

Video mixer:

feature name                    sup
------------------------------------
DEINTERLACE_TEMPORAL             y
DEINTERLACE_TEMPORAL_SPATIAL     -
INVERSE_TELECINE                 -
NOISE_REDUCTION                  y
SHARPNESS                        y
LUMA_KEY                         y
HIGH QUALITY SCALING - L1        y
HIGH QUALITY SCALING - L2        -
HIGH QUALITY SCALING - L3        -
HIGH QUALITY SCALING - L4        -
HIGH QUALITY SCALING - L5        -
HIGH QUALITY SCALING - L6        -
HIGH QUALITY SCALING - L7        -
HIGH QUALITY SCALING - L8        -
HIGH QUALITY SCALING - L9        -

parameter name                  sup      min      max
-----------------------------------------------------
VIDEO_SURFACE_WIDTH              y        48     4096
VIDEO_SURFACE_HEIGHT             y        48     4096
CHROMA_TYPE                      y  
LAYERS                           y         0        4

attribute name                  sup      min      max
-----------------------------------------------------
BACKGROUND_COLOR                 y  
CSC_MATRIX                       y  
NOISE_REDUCTION_LEVEL            y      0.00     1.00
SHARPNESS_LEVEL                  y     -1.00     1.00
LUMA_KEY_MIN_LUMA                y  
LUMA_KEY_MAX_LUMA                y  

laptop: ThinkPad P14s AMD gen 1
CPU: AMD Ryzen 7 PRO 4750U with Radeon Graphics

EDIT: this is what chromium reports in chrome://gpu

Graphics Feature Status
Canvas: Hardware accelerated
Canvas out-of-process rasterization: Enabled
Direct Rendering Display Compositor: Disabled
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
OpenGL: Enabled
Rasterization: Hardware accelerated on all pages
Raw Draw: Disabled
Video Decode: Hardware accelerated
Video Encode: Hardware accelerated
Vulkan: Disabled
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
WebGPU: Disabled
Driver Bug Workarounds
clear_uniforms_before_first_program_use
count_all_in_varyings_packing
enable_webgl_timer_query_extensions
exit_on_context_lost
disabled_extension_GL_KHR_blend_equation_advanced
disabled_extension_GL_KHR_blend_equation_advanced_coherent
Problems Detected
WebGPU has been disabled via blocklist or the command line.
Disabled Features: webgpu
Clear uniforms before first program use on all platforms: 124764, 349137
Applied Workarounds: clear_uniforms_before_first_program_use
Mesa drivers in Linux handle varyings without static use incorrectly: 333885
Applied Workarounds: count_all_in_varyings_packing
Disable KHR_blend_equation_advanced until cc shaders are updated: 661715
Applied Workarounds: disable(GL_KHR_blend_equation_advanced), disable(GL_KHR_blend_equation_advanced_coherent)
Expose WebGL's disjoint_timer_query extensions on platforms with site isolation: 808744, 870491
Applied Workarounds: enable_webgl_timer_query_extensions
Some drivers can't recover after OUT_OF_MEM and context lost: 893177
Applied Workarounds: exit_on_context_lost

and this is what firefox reports for video decode

HARDWARE_VIDEO_DECODING	
default	available		
user	force_enabled	Force enabled by pref