I think you confused the new NFT game which has an open source client, i dont remember what its called because my subconscious sorted it as dead-before-launch. EvE is entirely closed source with a small bit of API.
It would be ideal if they just worked with Valve to give them error reports from users using proton.
My main issue with proton8 was after about 10-40 minutes the GUIs would stop working, it would start with a few buttons then get worse. Flying in highsec was tolerable but lowsec wasnt viable.
Trying proton9 today.