I checked the completed file, but there was no --disable-dev-toolsin the package.json file...
Do you still have the previous old version?
F12 didn’t open either...
Viewing post in The loading never finishes...
I wrote the wrong chromium command line argument. It's --disable-devtools.
In any case, you can disable "Encrypt assets" (and, if the game is still stuck on the loading screen, disable "Source code protection"). This will revert it back to the R5.xx behaviour.
If this still happens, I'll send you a link via email.