Still the same. It tries to launch, I get a short blackscreen, and then it crashes again. I have sideloaded it into Heroic, and the log stops with these two lines:
INFO: [Frontend]: Refreshing sideload Library
WARNING: [Backend]: refresh not implemented on Sideload Library Manager
If I download and install it directly from Epic again, and simply check the box for it to run offline, it works just fine. But that kinda defeats the point, I want to be able to sideload it without having to authenticate myself, which should be possible according to the entry at PCGamingWiki