I hope you understand my bad English, but I want to help the community.
Installing IPFire native on an RPI4 - won’t work, but if you are using EXSi for ARM you can install IPFire aache. I’ve tested IPFire on an RPI3, but it’s too slow for me. With ESXi and IPFire (4Core and 2 GB RAM for the VM) it goes very quickly. I used a RPI4 with 4GB RAM with 8GB would be even better.
Here is a tutorial on how to install ESXi on an RPI (VMWare on a Raspberry Pi (ESXi Install) - Network Chuck).
I hope I can support the community