Sound does't work correctly

I have the Problem that the Sound for my bluetooth Headset under Linux, doesn’t work correctly. I had this Problem already and changed the driver that I use for my bluetooth dongle, after I did that, the Sound worked without any Problems, after I’ve updated the System the Sound Problems are back. My Bluetooth Dongle needs the rtl8761b drivers and these are the drivers that 've installed on my NixOS too, here is the snippet from my configuration.nix

  boot.blacklistedKernelModules = ["rtl8xxxu"];
  boot.extraModulePackages = with config.boot.kernelPackages; [pkgs.rtl8761b-firmware];

And this is the output from lsmod | grep rtl

btrtl                  28672  1 btusb
bluetooth             913408  36 btrtl,btmtk,btintel,btbcm,bnep,btusb,rfcomm
firmware_class         49152  10 r8169,btrtl,snd_hda_intel,xhci_pci_renesas,btmtk,nvidia,btintel,btbcm,btusb,drm