Great laptop, very powerful, Windows (Meh!) works well, Linux compatibility needs some work as it one of only a handful of Thinkpads that do not have great Linux support at this time

As of 6th February 2021 there its best to choose a recent Linux with a Kernel version of 5.8 and later, I tried a few but chose Kubuntu 20.10 as it seems to offer an easy route to a usable KDE Desktop, I may distrohop to another in the future as I've never really been a 'fan' of Canonical

If the Fn keys don't work on initial boot, there is a work around after booting put it to sleep at SDDM and the wake it up Fn Keys then work or..

This can be down by suspending to ram for 2 seconds during bootup to do this edit crontab using

sudo crontab -e 

Then add the following to the bottom of the file

@reboot sudo rtcwake -m mem -s 2

What this does:

@reboot = whan the system boots up 
sudo = run privileged
rtcwake =  enter a system sleep state until specified wakeup time
-m = use stated suspend mode
-mem = ACPI state S3 (Suspend-to-RAM)
-s 2 = number of seconds to suspend to RAM for 

Plasma audio settings select the advanced tab the select and reselect 'analogue stereo output'

More detail to follow

lspci information