Don't take it too lightly - especially if your phone is IP-based or if your internet access is earning your salary.
I just ran the port check test for my router port 7457 (and a complete test for computer and router) on this webpage:
https://www.heise.de/security/dienst...html?scanart=1
It's a German IT magazine publisher and generally trustworthy.
Maybe you'll find a trustworthy English page to scan your system.