Just noting I run an AX210 on my T440p. Bluetooth and wifi both work starting with kernel version 5.12 in my experience. I had it pinned to a specific version rather than latest like
boot.kernelPackages = pkgs.linuxPackages_5_12;
but slowly 5.12 and 5.13 were both removed as specific kernel versions in nixpkgs, so it's
boot.kernelPackages = pkgs.linuxPackages_5_14;
now which still works.
I eventually plan to just remove the line and use the default kernel, once the default kernel is bumped up to 5.12
boot.kernelPackages = pkgs.linuxPackages_5_12;
but slowly 5.12 and 5.13 were both removed as specific kernel versions in nixpkgs, so it's
boot.kernelPackages = pkgs.linuxPackages_5_14;
now which still works.
I eventually plan to just remove the line and use the default kernel, once the default kernel is bumped up to 5.12