With the cable connected to the PS5 login to the Hub's menu and see if you can see the speed of the network connection.
In our Hub 3's menu "Connected Devices" shows a table with Ethernet connections shown at 1000 or 100 Mbps.
Can you do the same on the PS5, does its Network Status info show the speed of the network connection (i.e. 10/100/1000) ?