Hello @GregoriusT, please copy your system information from steam (Steam -> Help -> System Information) and put it in a gist, then include a link to the gist in this issue report.
Okay then. Also that Sound Card might not be the one that is in use, but I am unsure how USB Sound Cards interact with the Software. In case its needed to be known, its a Sharkoon SB1.
Nothing extracted yet.
So I thought I would go and test some of the old Windows-Only Games I have, and Cossacks: Back to War did work just as well as it works on Windows, if not even better.
The Cutscene at Startup has to be "press key to skip"-ed away as it is just a Blackscreen (on one of my Windows Machines it does the same), and the Tutorial when I tried to exit it glitched graphics a little (I had that happen on Windows too a couple of times, so nothing unusual).
The pure existence of a wrapper around the Game fixed quite a few Bugs it usually has on Windows regarding Alt-Tab and also Multimonitor Setups, not to mention the sometimes occurring jumbling of icons due to resolution changes on the Windows Desktop in "Compatibility Resolution".
I honestly prefer running this on Kubuntu as opposed to Windows. This August was the best timing for me to get rid of Windows, I did not even know this Beta was a going to be a thing before I switched, but now I can finally get rid of all Microsoft garbage entirely! Thank you Valve! :D
Stats on my Machine:
zotac zbox nano ci327
Kubuntu 18.04
1.1 GHz Quadcore Intel Celeron CPU N3450 (64 bit)
2 Sticks of 4GB matching RAM
Game Directory saved on an SSD
No dedicated Graphics Card (Intel Graphics)
https://gist.github.com/GregoriusT/2c549cbef99af86527b03d5a799799ef
(P.S. I only tried this Beta to find out if Sonic-Mania-Plus would run on it, and it did, but you guys already got plenty of reports for that ^^)