FPS drops to 1 after 20 minutes of an online game, no issues in offline though

So my friend has been experiencing this when I play with him and another friend and we cannot find a solution so I’m posting here. It happens literally every game we try but it runs no problem offline. Benchmark on our computers are over 1200 too so It doesn’t seem to be any pc spec issue. We tried LAN server too and he managed to last 30 minutes before he dropped to 1 frame. All 3 of our clocks stay blue the whole time and his stays blue even when dropping fps. Nobody feels the effects of his lag either. Anyone experience this and have a solution? We’re all on the same wifi btw

Edit: when pausing, he doesn’t see that it’s paused for a minute. Yet he still has a blue clock. I also played with 1 Guy a lot who had a laptop from early 2012 and he never had this issue though he would lag, but not like this