can you recommend any (opensource or trusted) android apps to check who's using your wifi? or any cmd prompt code to search on the desktop?
a small doubt: can anyone hack your computer through WiFi? If so, How to prevent that (or) How to take measures after you think you been hacked?
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