Unfortunately the 5.10 series kernels had an issue during the build that I didn’t spot until it came to enabling apparmor in 5.15. This meant that the extra patches required for snapd strict confinement weren’t actually being added. The 5.15 kernels should work correctly again. You can get the latest kernel from https://github.com/diddlesnaps/WSL2-Linux-Kernel/releases/latest. This needs to be copied to <your user's home directory>\AppData\Roaming\wsl2-custom-kernel. This requires that your WSL2 be shutdown so that you can overwrite the original file, which you can force with wsl --shutdown.
I think there is an issue with the One Script WSL2 Systemd kernel updater, which I need to investigate, because this should happen automatically on login to Windows.