Brew is shit. I’ve had to use it, and wouldn’t chose to ever again. 32gig of RAM? For professional work? What is this, 2009? 4 ports is good, and good to hear about the sd-card finally. And you’re supporting the mac mouse? With the charging port on the bottom?
You may think it fine. But for the money I think Macs are vastly inferior to a decent thinkpad, dell, or even HP
You might be able to do mac address cloning for fiber ports, if you have openwrt or similar it usually offers it.
A firewall may not offer full routing and NAT though for ipv4 devices, or wifi if you need it, or ipv6, or many other features. I’ve also used a cable modem and stuck the router in the dmz which essentially makes it a passthrough device also in the past
Basically, play with it and good luck!