My desktop PC offline frequently. Try many ways to fix it but no good news. Such as changing power saving option, USB power option, etc. Will Try more method to figure it out.
1, I tried to connect my pc to 4G network still got same issue. So it’s not router problem.
2, I tried disable device saving mode via device manager still got same issue.

3, Tried to disable TCP/IPv6 still same.

4, Tried static IP it works. But why?

5, The final way is to do network reset then everything become fine.