There is a workaround for proxmox in easy2boot and agFM/grubFM for UEFI
ProxMox 8.2 ISO - boot using partnew\e2b. At proxmox grub2 menu, select an Install menu entry and press 'e' key. Then edit grub2 menu to insert lvm2root=/dev/sdX4 just before 'rw' and press F10 to boot. e.g. /dev/sdb4 if USB is sdb
So maybe you could boot the grubfm_multiarch ISO via Ventoy and then use the grubfm menu system to boot to proxmox using the lvm2root hack?
https://github.com/a1ive/grub2-filemanag...tiarch.iso
When using e2b or grubfm, use /dev/sda4 because partition 4 will contain the iso contents,
I have tested on an MBR Ventoy USB drive with UEFI64 boot (not tested GPT USB drive)
ProxMox 8.2 ISO - boot using partnew\e2b. At proxmox grub2 menu, select an Install menu entry and press 'e' key. Then edit grub2 menu to insert lvm2root=/dev/sdX4 just before 'rw' and press F10 to boot. e.g. /dev/sdb4 if USB is sdb
So maybe you could boot the grubfm_multiarch ISO via Ventoy and then use the grubfm menu system to boot to proxmox using the lvm2root hack?
https://github.com/a1ive/grub2-filemanag...tiarch.iso
When using e2b or grubfm, use /dev/sda4 because partition 4 will contain the iso contents,
I have tested on an MBR Ventoy USB drive with UEFI64 boot (not tested GPT USB drive)