Is L3 Switch Needed If Netgate is Routing VLANs?

I am rebuilding a network and we would like to create a few VLANs in the process. If we are using a Netgate unit as firewall, do we need a Layer 3 switch? We have a Netgate 6100. If that handles the VLAN routing, would something like a Unifi Switch 24 PoE (USW-24-PoE) work for our switch?

Is there a reason why this would not be a good idea?

No, you don’t a L3 switch. They are typically used when large volumes of traffic need to be routed from one network to another network because doing it at the switch is faster than doing it at the router.

You just need a switch that supports VLANs which the UniFi switched do. As long as the routing is being done via pfnsese then you don’t need a switch that supports layer 3 routing.