Ok, based on the box.log file I got a LLM/Claude debug session going and it was pretty quick showing me, that there was a docker container (postgres) running that was attached to the Cloudron Network, but not managed by Cloudron. I think that was something I set up super early, before I understood how Cloudron works. Claude helped me dettaching it and now the update went through without issues and everything is running again. Thanks for the hint with the box.log file @joseph !