Is it possible to run on an old x86 and replace start9?
⚡Version 1.12.0 of RaspiBlitz Released⚡
New data layout with optional NVMe boot on Pi 5. On Proxmox now separate data & storage drives. Still works on Pi 4 - but 64GB SD card + 2TB SSD/NVMe now recommended. Many updates & fixes.
Download: https://docs.raspiblitz.org/docs/setup/software-setup/download 
Discussion
Pi’s are about as expensive as a refurbished micro pc. Can i install, run headless and ssh into it.
Yes its possible - you need to install a plain headless debian12 and then run the raspiblitz build script: wget --no-cache https://raw.githubusercontent.com/raspiblitz/raspiblitz/v1.12/build_sdcard.sh && sudo bash build_sdcard.sh -u raspiblitz -b v1.12 -f 0 -d headless