Mostly because i thinkt hese would be great to play with ESXi on them. 🙂

As far as I know, it only has the eMMC and no dedicated "firmware" storage (e.g. SPI flash) like the Jetsons and CM4s have, so if you install some kind of platform firmware, you'll have to partition the eMMC carefully so as not to overwrite it by accident. But given that, there IS a port of EDK2 for the RK3588:

While there is some port of some UEFi for RK3688, there's no official UEFI and the RK1 won't have UEFI