Both opnsense and pfsense allow custom DNS entries so you still have that as an option. Probably the other options do too but you’ll just have to verify.
But if you want to keep it simple I would just keep the pihole as a separate device. A lot of the built in options aernt quite as easy to setup and don’t have the best UI compared to pihole IMO.
I’m partial to mikrotik gear, the CRS305 has 4 sfp+ ports for around $150.