It's the other way around. Wine-ge will be discontinued and you use ULWGL to use proton-ge outside steam. It's not a "launcher" launcher like lutris or bottles, just a script to launch proton without steam.
I think people are getting the wrong impression because it said "unify" in the title. This is mostly GE want to obsolete wine-ge/winetricks and focus on proton-ge and protontricks/fixes. Nothing out of his works, at least for now. Everything else should work the same.
It's the other way around. Wine-ge will be discontinued and you use ULWGL to use proton-ge outside steam. It's not a "launcher" launcher like lutris or bottles, just a script to launch proton without steam.