It silently messes with the kernel boot flags which breaks the boot process If you do get it to work it silently adds extra broken repos which make it impossible to install packages.

Why would any distro want to support a tool that intentionally breaks things? Ventoy could just boot ISOs without messing with them and everything would work fine, but the developers insist on injecting garbage.

SuSE doesn't ship ventoy and the installer does boot and work just fine. It's likely a bug in ventoy. SuSE doesn't test that and why would they?

Perhaps ventoy doesn't like SuSE.

I’ve had trouble installing proxmox with ventoy, I had to install debian and then proxmox as a package. AFAIK there isn’t really an alternative to ventoy?

You really shouldn't trust ventoy.