Just a quick note - I just installed 5.14.21 and finally all my problems are solved at the same time Specifically, I have stable Wifi-6, and sleep and wake up on AC power (which I need to wake up the laptop with the power button on the dock since I have it on clamshell) are all working.
Bluetooth is OK, too.
For Ubuntu, .deb files here:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.14.21/
You need these 4
linux-headers-5.14.21-051421_5.14.21-051421.202111210831_all.deb
linux-headers-5.14.21-051421-generic_5.14.21-051421.202111210831_amd64.deb
linux-image-unsigned-5.14.21-051421-generic_5.14.21-051421.202111210831_amd64.deb
linux-modules-5.14.21-051421-generic_5.14.21-051421.202111210831_amd64.deb