Update: my issue got resolved after about 24h! Notarizing fine again.

I have also hit this issue today, is there anything I can do to get "unstuck"? 96cb07db-27c3-46fc-8122-b2e78020d3fa

Ah I just found the solution, I needed to add NSBonjourServices to my app extension's info.plist specifying the services I'm looking for

You can easily fix this yourself, just add QuickLookUI to your linked frameworks and set it to optional: https://community.folivora.ai/t/bettertouchtool-will-not-launch/38688/4?u=andreas_hegenberg