Ahoy, and welcome to the high seas! There is a handy Wiki that may cover a lot of your questions, I suggest you give it a look and then follow-up with any additional questions you may have. (The link is also available in the sidebar of this community, if you ever need to find it quickly again without finding this post!)

EA App was the only issue I faced, otherwise all three games ran great via Proton. Tried using old Origin rollbacks for offline play, but it would break after a session or two. Recommend playing with an online connection if using a copy that requires the EA App.

How does it compare to Obsidian? Other than being FOSS which is a win.