testing it on a Ryzen 3250u.
right now, it panics while starting init, in pmap_pvh_free with KASSERT(pv != NULL, ("pmap_pvh_free: pv not found")):
vm_map_delete -> pmap_remove -> pmap_remove_ptes -> pmap_remove_pte -> pmap_pvh_free
setting vm.pmap.pg_ps_enabled=0 avoids the above panic but ends up in an integer divide panic (which seems unrelated, happens even with vanilla kernel)