Network Disconnect on Linux guest VM under Windows Host

[Ceri]

This happens overnight, but I have the windows machine to never suspend/hibernate, so I don't understand why the network connection completely goes away. Any ideas on how to fix this. The network completely goes away, and doing an ifdown/ifup on the Linux VM side doesn't bring it back, so I've been rebooting the host.

Setup: The network connection is bridged, its a Windows 10 host and guest OS Linux Mint 19.2 (Tina).

Any ideas on what I could do to stop this disconnect?
Secondary, if this can't be solved, is there a less drastic solution than rebooting the box to get the network interfaces back up.

I do have "ServerAliveInterval 60" set on my Linux guest VM. I did try due diligence, and search for "network disconnect" on the forums, and didn't find anything from after 2015.

[socratis]

We need to see a complete VBox.log, from a complete VM run, where the problem occurs:

• Start the VM from cold-boot (not from a paused or saved state) / Observe or recreate the problem / Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

Also, if you could cross-reference that with logs from your router, that would be great. I do NOT need anything public (like your router refreshing its IP), but leases that are given out/renewed inside your LAN.

Finally, does this happen if you use "NAT" or "NAT network"?