I have been using an Xfinity Gigabit Extra internet plan successfully with my current config: Netgear CAX80 Gateway/Cat8 cable from 2.5 multi gb port connected to 2020 Mac Mini M1 10 Gb ethernet port.
5 port 10/100 D-Link switch DES-1105. $5 + shipping. Netgear Gigabit NIC GA311 $5 + shipping. Intel Pro 1000X Network Card Gigabit - A51562-008 PCI-X 133. $10 + shipping. Rivera Sound Card. $5 + ...