For a while I have been planning to switch from an all-in-one wifi router to having separate devices because that way they can be upgraded piece by piece instead of having to replace the whole thing.

I am confused about the role of the firewall.

If I have a router running OpenWRT, does it have a firewall included? Either by default or by installing certain packages?

Or is it required to have a separate firewall running opnsense/pfsense?

If not required, what would be the benefits that would lean in favour of separate firewall?

use case: small home network 2-3 users. some internal self hosting and maybe one day external self hosting.

ETA: The best internet I could subscribe to where I’m at is 1024 Mbps down, 50 Mbps up. So don’t worry about wasting fibre speeds. :(

My assembled components so far are: router, WAPs, switches, ethernet cable and cable modem.

Thanks for any advice.