WiFi Sharing: Gnome and KDE Plasma

[nPrevail]

I’m aware of setting up WiFi sharing/hotspot via configuration.nix file (Internet Connection Sharing - NixOS Wiki).

I’ve been using GNOME for awhile, and I’ve normally installed GNOME as my DE by default, and WiFi sharing works from the WiFi menu. Even better, is that I’m able to produce a QR code from the WiFi settings.
Using GNOME’s WiFi settings to turn on a hotspot bypasses the need to add the config in our configuration.nix file.

On the other hand, I recently started using KDE Plasma, and installed Plasma during my initial installation, and WiFi sharing doesn’t work. I’ve been struggling to get my devices to connect to the hotspot. Even though it can be detected, no device can connect.

Any idea why GNOME’s hotspot works, but KDE Plasma’s hotspot does not?
My configuration files are practically the same, except that one installs GNOME and the other installs KDE Plasma.

I know I can add the configuration into my configuration.nix file., but I kind of like being able to produce a QR code, and I like using the GUI more than terminal (for WiFi matters)

Here’s screenshots of my settings:

[jtojnar]

For me, my phone cannot connect even in GNOME until I open DNS and DHCP ports in the firewall, see Nftables firewall blocks requests to dnsmasq DHCP · Issue #263359 · NixOS/nixpkgs · GitHub.

[nPrevail]

Looks like the same change also broke NetworkManager Wi-Fi hotspot. Without DHCP port open on firewall, my Android phone will get stuck on “Obtaining IP address” and without DNS, it will report not being connected to the Internet.

As you mentioned in that GitHub link, this is exactly what happens when I try to share and connect WifI to my Android phone, and also when I try to connect with another computer.