Sorry, I thought you said you already had a third party router.
When you changed hubs did you also change the PSU?
Alternatively, try my suggestion of a direct PPPoE connection to the ONT to eliminate the hub.
Yeah we’ve changed the power supply,
Openreach also changed their modem and changed the power supply to that and we’ve replaced all the Ethernet connection wires between the modem/router- still ongoing
How do I do a direct PPPoE?
I think you said you have a Mac
https://support.apple.com/en-gb/guide/mac-help/mchlp27142/mac
Or just Google direct PPPoE connection
Username is bthomehub@btbroadband.com and password BT