The resources for this phone seemed to be scattered around the internet so I went ahead and wrote a simple on guide for it.
It covers: Rooting the phone, Installing Magisk (root), passing SafetyNet and debloating the phone. The phone is very barebones once you uninstall most of the apps! I like it a lot.
The F21 Pro is actually a really nice and capable phone, I like it. Even the 3/32 model is pretty useable. I mean really, no toll on performance.
Only thing with the 3/32 is that if you want to use ROMs, most likely you need to fully format the device EXCEPT THE BOOTLOADER, I mean other than that, wipe the whole thing down to nothing. It's pretty scary, but then you can Format All + Download in SP Flasher for the ROMs.
Be really really sure you have backup of your factory ROM.