I suspect that if you connected to your work vpn from a personal VPN IP address that may raise some questions. “Dave keeps connecting from inside Amazons data center, thats weird”.
Turning on wifi to scan would be trivial technically. Hidden GPS maybe, but its more likely that they would just have an overt GPS module if they cared.
A wired in airtag or similar would probably be doable, and wouldnt be visible to the OS.
Latency analysis would probably be quite tricky. If you had starlink or dialup your latency would be pretty bad to begin with.
Realistically, if the employer was concerned about company data leaving the country they wouldnt be allowing WFH at all.