This is a quick video that shows how to load Red Hat Enterprise Linux 9.x Beta on a Raspberry Pi 4. This is just one brute force approach; lots of other more automated methods are possible. This is currently unsupported, but lots of fun nonetheless.
I've only tested the following:
UEFI firmware,
USBC - power
Mini-HDMI to a remote monitor
USB keyboard
a USB thumb drive with RHEL 9.1 Beta.
and the on-board wired ethernet.
Be sure and select a good thumb drive, or even an SSD drive for best performance.
Red Hat is doing some amazing things with Edge Automation, but that's beyond the scope of this video.