A new post on the Arch forum suggests trying with the new Xe driver instead of i915 and setting a fixed amount of VRAM. The first part I am testing now. Try adding this to the CMD_LINE (grub/systemd-boot)
i915.force_probe=!7d55 xe.force_probe=7d55
If that still doesn’t work, you can also try adding:
xe.vram_bar_size=2048