Yeah, using Linux Steam leaves you almost on your own. But I've found a good place at the Proton GitHub. Here:

https://github.com/ValveSoftware/Proton/issues
There you can find more info on the Shader Cache problem and several workarounds.

There are also another line of Proton you could try, it's the "GE"-line. Those versions can be downloaded and manually copied to the steamapp directory.  I'm running those for some months now.

There were some problems here too with slow building of shader cache - every startup. But in my case I could disable it. Supposedly there is some minimal lag sometimes when the game is starting but I haven't noticed much.

Good job! I'm into Xfce but I've used Mate before too. Mate is nice and your goals are the best!

AI seems to be paranoid?
https://www.youtube.com/watch?v=65YIlwxBuvM

I'm reading a biography of George Orwell ("1984"). "The Ministry of Truth" by Dorian Lynskey. Really good! Generally biographies gives you a lot of history of the times concerned in the book. This book writes about circa 1880-1950 and touches the Spanish civil war, several other big authors of the time like H.G. Wells, just to mention one. As you might already know Orwell/Eric Blair partook in the civil war in the trenches of Spain. 

The book 1984 might be hot even today with all the Big Tech and polarization going on in society. But I do not know if I can stand re-reading it right now. The future doesn't seem too promising, I think.

It might be time to read George Orwell's "1984" again...

Made the above posted script as an init.d script instead. But beware, this init script runs the actual script as normal user - which is NOT recommended. Tested this and it works. The reason is that sometimes when an x session is running and the .xsession-errors file gets rotated, it won't be written to again. So running it at shutdown or reboot should work better.
Script:

#!/bin/sh

### BEGIN INIT INFO
# Provides: /home/$USER/bin/logrotator for .xsession-errors
# Required-Start: $syslog
# Required-Stop:  $syslog
# Default-Start:  0 6
# Default-Stop:   3 4 5
# Description: Rotate .xsession-errors as user $USER, creates backups. Should run at shutdown only without X
### END INIT INFO

#. /lib/lsb/init-functions

case "$1" in
  start)
	touch /run/logrotator.pid
	chmod 600 /run/logrotator.pid
	chown $USER:65534 /run/logrotator.pid
	sudo -u $USER /home/$USER/bin/logrotator
	;;
 stop)
	killall logrotator
        ;;
  *)
        echo "Usage: $SCRIPTNAME start" >&2
        exit 3
        ;;
esac

Actual script (home/$USER/bin/logrotator):

#!/bin/bash
for i in {9..1}; do
    if [[ -f /home/$USER/.xsession-errors.${i} ]]; then
        mv -f /home/$USER/.xsession-errors.${i} /home/$USER/.xsession-errors.$((i+1))
    fi
done
mv -f /home/$USER/.xsession-errors /home/$USER/.xsession-errors.1
touch /home/$USER/.xsession-errors
##Might not be needed:
chown $USER:$GROUP /home/$USER/.xsession-errors

Edit $USER and $GROUP to taste.

PS. As you can see, I do not know what I'm doing, so don't try this at home.

Oops! On my other Devuan machine .xsession-errors was 830MB!!! But I thought I share my findings for a solution of the growing file size (not the errors )

Create a file like this in /etc/logrotate.d/my-xsession-errors

$HOME/.xsession-errors {
missingok 
notifempty 
copytruncate
compress  
weekly  
rotate 5
}

This will rotate the file weekly and keep 5 old files. Edit to your needs.

EDIT: added copytruncate because sometimes when the .xsession-errors file get renewed, it is not written to anymore (in that session).

Thanks for this thread! My .xsession-errors was 26 Mb. Big! Mostly BS, some GTK errors, the weather applet complaining, xdotool missing for some old script.

I chose ralph.ronnquist's no 2 script and running it manually for now.

Finally my two brain cells got it! Thank you!

=if(or(B281="Sat";B281="Sun");"0";"1")

(Sry for the very late answer)

Yes it's bad and it has even gotten worse over the years. Gobbling up more and more features. A big blob.