Although for some of us this is a well-known problem, it has appeared again with the release of DOOM: The Dark Ages so it's worth a quick PSA to remind people about Denuvo activation limits with Proton on Linux, SteamOS / Steam Deck.
While this is stupid, it's also minor and doesn't really deserve such clickbaity titles. You'll only be locked out for 24 hours, which is not long, and you'd have to switch Proton versions 5 times within 24 hours for this to happen, which should be very rare to begin with.
I play exclusively on Linux/Proton for years now and at the MOST I've switched Proton versions like 3 times within 24 hours, 99% of the time I switch them never (because 99% of the time it just works) or just once (e.g. switching from regular Proton to Experimental or GE-Proton, which might help wth very new games). That means I would probably never be affected by this.
I"m not trying to defend this, this limitation should not exist, but I'm trying to position this correctly because the titles are misleading clickbait, they suggest you'll be locked out permanently.
Remember it from resident evil village and elden ring. If you set proton to hotfix it can update and count as changed. Therefore I set all games to use just to latest proton ge.
Not Ishin though, and that's a shame. No one patched Denuvo from it too. It's not a mainline game, but from what I've seen, it may become my favorite entry one day :(
Getting locked out for 24 hours for changing between 5 different versions of Proton isn't the worst, mostly just sucks for people who test stuff or benchmark.
Same thing also happens on Windows if you replace hardware (for example doing benchmarking across multiple gpu models)
Obviously fuck denuvo, I hate drm as much as the next guy in this community. But being locked out from using more than 5 different versions of Proton in 24 hours isn't that bad, you can just switch back to one of those 5 and it keeps working. (assuming it worked in the first place, which at this point with how good proton has gotten it probably does)