I tried every possible guide and none of them worked for me, here's what I did:

(Be sure that there is no prefix and that you have Proton 5.0-10 installed.)

1. Launch Steam via CLI.
2. Install latest GE-Proton (for me, at time of writing, is GE-Proton-9.5).
3. Select as compatibility tool the one you just installed and launch the game, this will create a prefix with the right dependency as per the shotgun method (make sure to have my environment variables set, haven't tested without them).
4. If needed, spam the "Play" button until the game is reported as "Running" and you don't see anything happening in the console, should look something like this:

<YOUR LAUNCH OPTIONS>
Game 244210 created interface <SOMETHING> // repeated many times
Game 244210 method call count for IClientAppManager::<something> // repeated 3 other times
Game 244210 method call count for IClientUtils::<something> // repeated 2 other times
Game 244210 method call count for IClientUser::GetSteamID : 1
Uploaded AppInterfaceStats to Steam

5. Stop the game, set compatibility tool to Proton 5.0-10 and change launch options to the ones at the top of this report. (don't forget to modify the path to your SteamLibrary)

P.S.: This guide builds on top of many others guide but, generally speaking, the same methods are mentioned in quite every report and/or post. If any step is "unclear" or "too generic" please refer to other posts and your doubts will be clarified immediately.

I haven't tinkered with shaders and mods yet, however I don't think I will find another way of running this game (except dualbooting Win10, which I won't ever do) so I'm already posting this.

Hope you don't waste as much hours as me, GL HF <3 (if you look at total playtime (4 hours) when I created the report, this is all time that went into waiting for dependencies to be installed and/or something that was happening in the prefix, now add 2-3 hours for research time on Google and for the "Launching" status)