I have this setup with a Starlink satellite connection with an ethernet connection into WAN 1 and WAN 2 as a failover to a VDSL connection via a Draytek Vigor 130 modem. That works fine and I've been getting speeds of up to 250mbps on occasion. I now seem to be getting slower speeds and looking at the dashboard it's showing WAN 1 as coloured orange which is a 100 mbps setting. Is this a router setting somewhere or an automtic recognition of the Starlink ethernet connection which has changed?

In "General Setup" of WAN you can set the speed of the WAN ports - first thing to check I should have thought.

Did, set to maximum 0,0 and auto detect wherever that appears.

Dodgy ethernet cable between modem and Router? Tried swapping it out? Its happened to me on occasions.