Sorry for the late reply,
yes uefi+secure boot.
I Installed the Server on 10.Okt.2023 at 16:09:27, with Kernel 6.2.16-3, Debian 12.2.0-14 (Thats info from the oldest boot log)
So it was the Proxmox 8.0 ISO.
there is maybe broken text in the term.log -> that was the ncurses window, which asks...