@as-21 said in DD WRT router as guest network with limted bandwidth:
What i basically want to do is DD WRT as separate network
Well that is not what you did - you just put in dd-wrt as a downstream nat router...
If you want it as a GUEST network - then use it as just an AP and connect it to another network on pfsense be it another physical interface on pfsense or via a vlan.
Use one of dd-wrt lan ports to connect it this new guest network, turn off its dhcpd and put its lan IP on whatever guest network you create on pfsense.. Setup the firewall rules to allow this guest to do what you want.
Does that switch you list do vlans?