The OPNsense embedded AMD firewalls [1] [2] [3] are really powerful and would be excellent devices to run pplznet firmware on. I tested the DEC700 series quite thoroughly with OpenWrt and since Version 22.03 they run very smoothly and stable.
They deliver lots of CPU performance and dual SFP+ 10G ports. The devices are somewhat expensive though when you compare them to off the shelf routers.