Hi mickc6
VM don't supply a hub5+. Which VM hub do you have? It will either be a hub 5 or hub5x. (VM normally only supply a hub 3 for speeds up to M600, or if you are in a full fibre area (XGS-PON it will be a hub5x)
What actual speed are you are receiving directly to the hub using https://samknows.com/realspeed/ ?
You say you've tried 3 different ports on the PC. Are they ethernet ports (unlikely) or USB ports using your TP-Link dongle?
What speed is your TP-Link dongle capable of receiving?
Ethernet speeds of less than 100Mbps are usually due to a bad ethernet cable.
Which ethernet port are you using on the hub5?
Have you checked that the PC's adapter settings (speed & duplex) is set 1.0 Gbps Full Duplex, or higher.