DMZ Setup. Should I use two firewalls, or is one firewall with VLANs enough.

I host a few servers from home and want to move the public ones into a DMZ. I was originally planning to put the DMZ on a separate VLAN, but a lot of sources I’ve found go a step beyond that and put the DMZ behind its own firewall. As far as I can tell, the two options are functionally the same and adding another firewall just makes things more complicated for no reason. Is there any benefit to having a separate firewall? Why would someone choose one option over the other?

My firewall is pfSense. The DMZ is for wireguard, a web server, and a handful of game servers.