@larrygs Ah, so the PC's also have SFP+ ports, not RJ45?
Anyway, sounds like you are on to something there, with the Qotom (2.5G) and 10G (TP-Link) connection. So in that case you have an RJ45 module plugged into the TP-Link and ethernet cable to the Qotom, right?
And that port is set manually to 1G in pfsense as well, or is it set to auto?
I have read that there were problems with the i226's but I thought it was fixed in 2.7.2. And one solution is actually to virtualize pfsense on the Qotom (Proxmox) and give it a virtual NIC, instead of a full pass thru. Assuming the drivers in debian are working... You will not have any problems getting the full 1G even in such a setup (actually way more than that with that CPU).
The only issue I have had with the SX3008 is that it doesn't autonegotiate to 1G and that it overheated. But I have not tested with any of my devices that have 2.5G NIC's, as they are connected to a SX3206HPP which works fine @2.5G.