pfsense squatted on competitor domain and used underhanded/defamatory practices: opnsense.org/opnsense-com/
If you don’t mind the drama, both PFsense and OPNsense are perfectly competent router OSes.
Regarding hardware:
OPNsense also sells rack-mountable server hosts.
OP may not actually need a rack-mounted server – I have several machines just sitting on a 2u rack-mounted shelf. My opnsense install runs on a cheap protectli box, and there’s enough room for a handful of raspberry pis and their power bricks on the shelf next to it.