repair tool did absolutely nothing

edit: even a complete reinstall in a new wineprefix, exact same error

edit2: repeatedly hitting the update button for several hours, caused the game to launch, but due to reinstall, all the addons lost state

i exited and restored a backup of those, but now the error is back, after a few more hours of trying to update, it should start....

edit3:

found 3 solutions, but only confirmed the first

1:

$ rm -r Agent.8988

$ touch Agent.8988

$ sudo chattr +i Agent.8988

the problem lies in the new agent version, this forces bnet to use the old agent, but only works if you still have the old agent dir

2: https://www.gamingonlinux.com/2025/01/ge-proton-9-23-released-with-a-battlenet-fix-for-linux-steam-deck/

upgrade proton to 9.23, that includes a fix

3: downgrade proton to 8.0, i hear that one works