If this is an ethernet issue, this could be the problem as posted by barryrowns on Reddit:
"level 2
barrybrowns
10 points ·
1 year ago
Here we go, found a YouTube video (link below, not my video) from a guy explaining this. If you have an Intel network card, Windows enables Wake-On-Lan so that the machine can be remotely started when shutdown. Unfortunately, this prevents Ubuntu from taking full control of the card. In this case, however, the network doesn't work at all in Ubuntu, while you're network just seems to run a lot slower. This pertains to wired Ethernet connections, though, so maybe it really is a driver issue. But hope this might be able to help someone else.
https://www.youtube.com/watch?v=aQMd476d8Ug"