But now I run into the issue, if the install is finished my pc goes into a boot loop, without successful boot. Any advice?
You mean you went through the install just fine, but at the end, when it is supposed to reboot into the actually installed PVE, it instead keeps rebooting? What do you see on the screen as it starts booting?
Worst case, you will have to use that LIVE Debian approach, boot from that independent USB and explore the boot log and go from there.