Known issue related to fedora increasingly requiring more RAM and issues that would be shown under sys-net by keeping a scrolling system journal before the issue happens sudo journalctl -f to see logs when you loose network (and hopefully push devs to increase the sys-net/sys-usb default of assigned memory). Was reported in different threads for sys-usb (camera disconnection, usb proxy failing, etc) and sys-net (after resume of suspend, on high network throughput etc).
You could either assign more memory to those HVMs (no memory ballooning for sys-* machines), try to tune systemctl there, rely on a minimal template, switch to debian… But the simplest is to assign more memory to the faulty sys-net/sys-usb: