I haven’t check in a while but I think I remember that proprietary app either do not have security audits or they failed them. You should check though I am not 100% sure.
Sadly doing it on the router would not be enough. Not a problem if you are browsing of course. But if you host, needs to listen on a specific port or whatever it gets annoying. And obviously piracy.
No worries, I was fully ready to discover they were French