I got this running under Steam with a (custom) Proton build. Seems to work flawlessly and is very easy to set up - great performance in high settings and resolutions!
First:
1) Install Steam.
2) From inside Steam, from the options at the top left: Steam > Settings.
3) In the settings window > Steam Play. Tick Enable Steam Play for Supported Titles and Enable Steam Play for all other titles.
4) Download and install Mechwarrior Online from inside Steam.
Then:
1) Exit Steam (if running)
2) Open terminal
3) Terminal Commands:
mkdir ~/.steam/root/compatibilitytools.d
wget https://github.com/GloriousEggroll/proton-ge-custom/releases/download/5.2-GE-2/Proton-5.2-GE-2.tar.gz
tar -C ~/.steam/root/compatibilitytools.d -zxvf Proton-5.2-GE-2.tar.gz
Close terminal
Lastly:
1) Start steam and from the Steam Library, right click on Mechwarrior Online and select Properties.
2) Click Set Launch Options and use
%command% -noprompt -anygpu
3) Tick Force the use of a specific Steam Compatibility Tool and select Proton-5.2-GE-2 from the list.
Notes:
This assumes you have Wine, Wine Tricks and DXVK installed. They should be available in the repository/software store for your distro - if you're having trouble, it's probably because you simply haven't installed one or more of these.
Edited by Angelwolf, 16 June 2020 - 04:00 PM.