I tried the fix for the touchpad that bjdduck kindly posted before (post #37) on the latest Manjaro 20.2 and Pop_os 20.10 releases. It works on both although for some reason on Pop, right click is not working.
As for the brightness control I started using "redshift" from the command line to control the brightness. It's not an ideal solution but at least for the moment i don't have to wear sunglasses to look at my screen
Just in case anyone is still habitually using a USB mouse... I tried using my own fix earlier this week to find the first directory didn't exist. Turns out, the trackpad now works in Arch, and it responds and behaves better than in the previous solution.
It had been a while since I'd tried using it (habitual USB mouse use), so I can't say which update did it, but if it hasn't propagated to other distros I would expect it to soon.