xyz123: I can not test that now because I'm setting up a new system. Anyhow, I hope that these workarounds will work w/o the Galaxy client as well.
"Genesis Alpha One" looks (from the gamne trailer) like a shooter for me with some ship-/crew-building.
Please correct me if this is "Mass Effect"-like with a decent story, communication with several NPCs, (side-)quests etc.
It should as neither of those two are required to run GOG Galaxy via Linux. Though you will need to possibly setup potential libraries if not using a version of Proton and you'll likely need d3d stuff if going into it blindly with a fresh go of a prefix. Though, I figured you knew this at least.
Instead of going through the headache of the other methods. I just used GOG Galaxy because it's easier to download and update a game and to use cloud saves. Since I jump between the two machines, I love those cloud saves. I just wish there was a Linux client. =/ Long live Steam for most games until that happens.
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Edit: To answer your edited question.
Genesis Alpha One is kind of a mix of games. You setup your crew in a menu then go into a top down little menu to build your ship. Once you do that you're basically managing your ship in a first person view. You'll travel space scanning areas with the computers in the ship. Then assign crew members to stations, grow crops, get loot, and shoot alien enemies that come into your ship with the cargo. I guess the best thing to compare it with would be FTL, but more graphics and first person. Yet even that isn't the best comparison.