Bazzite install failed at writing EFI partition - tchncs

Hey, I hope someone here can help me with Bazzite. I already tried to ask at a Bazzite community, though it doesn’t seem to be active enough. ( https://discuss.tchncs.de/post/52581032 [link] ) I failed to install Bazzite besides Windows10 (same SSD) and Ubuntu (different SSD). I got the error that grub2-mkconfig exited with code 1. It did not create an entry in my efi partition (checked in Ubuntu and only saw one Ubuntu and one Windows directory). I checked the logfile mentioned in the error dialog, though that basically just said the same. No further information. As I wanted to overwrite an existing old ubuntu install on that SSD, I chose to install on a shared disk and then reclaimed the storage space by removing the old root and swap partition of the old Ubuntu in the resulting dialog. The partioning for Bazzite is then done automatically on the resulting free space. Can you help me with this? All I could find online was either not fitting the problem at all and/or showing a totally different install process (probably for old Bazzite versions). My hardware is rather old. Ryzen5 CPU, SATA SSDs and HDDs and a Geforce 1060 3GB. I hope to now completely ditch Windows with a replacement for gaming. Thanks in advance for any help with this problem