Just log into your routers admin panel and see if there are any online devices online that arent yours? That would be my goto because then you can just block them from the panel?

otherwise via linux cli you can do arp-scan and youll see online devices in your subnet. Theres also a few options to scan different interfaces

Limpopo is definitely more backward. But Free State does have that small town redneck vibe going for it in many places. Also dont talk shit about my Brakpan. It gets that reputation because Springs people holiday there