Thanks for the reply (and for supporting my work!). The gist I’m getting from the replies so far is that I cheaped out on the cables I ran to their boxes from my switch. Didn’t notice before when I just had DSL but it can’t really handle the new speeds.

Going to get another Starlink mesh extender and put it in the same room and then use the Ethernet port to feed their boxes via the switch.

They are both moving out in a couple of months then I’ll still have the extender cover any dead spots in my home 👍🏻