I'm still having regular freezes with Launchbox since the .NET Core change. It's quite frequent and really just takes me clicking on a few titles before nothing will load for a good minute or so.
I've definitely noticed when it does work it's getting a lot faster but these freezes haven't really stopped for me. An observation, in one of the older logs I sent through you would have seen quite a few JSON parsing issues with RetroAchievements, I'm still getting those. I've also noticed the icon graphics for the achievements are the only thing not loaded when these freezes occur.
EDIT: I'm certain it's the RetroAchievements. If I remove my credentials and test then everything is fine. I can click on as many titles as I like without the issue.