I’m not talking about the situation where Steam delisted Dolphin from the store, but what I’m experiencing may be related to that. I believe Steam might be blacklisting Dolphin even when added as a non-Steam game. It sounds crazy but hear me out. I try adding it to Steam to make use of launch options and Proton. The issue is, it straight up removes the non-Steam Dolphin I added from my library. I have experienced this 2 times now: First, adding the official linux package (Arch extra repo) as a non-Steam game, which shows up as an entry automatically under /bin. I noticed after I left Steam for a while and came back, the entry for the game was greyed out as well as all options, directories, launch options. It’s as if I went in there and removed it all but I definitely never did. I wrote it off as a bug, used another method and moved on.

Second time was today. I am attempted to manually add the exe version of Primehack which involves a version of Dolphin. I added this exe as a non-Steam game, and got it running for a while. Exactly the same as last time, when I left Steam and came back a while later, Dolphin is gone! Now this perplexes me because I have other games added as a non-Steam game and they stay working fine, using the exact same methods I used Dolphin. And I experience it on both the linux version, and with Proton. Can’t be a coincidence. Could someone else try to replicate this? Download dolphin, add it to Steam as a non-Steam game, and see how it behaves after you relaunch Steam.