Thanks for helping.The pre-defined option was removed for now as with the serial terminal entries the menu got overly crowded, and one can always pass that option to the kernel command line easily any way, see this post: https://forum.proxmox.com/threads/proxmox-8-installer-freezes-at-boot.129341/page-3#post-608469
I read the post and still can't find it, when it doesn't crash it doesn't find the iso.
My computer has an NVIDIA graphics card, so it crashes when I try to start in graphics mode and in terminal mode it also crashes as it tries to load the drivers.
When I press `e` and type nomodeset it shows:
searching for block device containing the ISO proxmox-ve-8.1-1
with ISO ID `1417249e-...db54a0`
testing again in 1 seconds
testing again in 2 seconds
Error on device with valid ISO Found, please check your installation medium unable to continue.