I’m aware most ISPs do not allow for port 25 to be open for email use outside of business licenses, but at what level is that controlled? Can I get around that by owning my own router? Owning my own modem or ONT? Or is this just a thing they mystically control further up the pipeline that a relative layman such as myself can’t get around?
They do that upstream, so there’s nothing you can do on your router to change that.
One solution I’ve used in the past is run hoppy.network to get a public IP (it’s basically a VPN). Then your home computer has all ports open on that IP, since everything goes through an encrypted tunnel.
hoppy.network seems like a very expensive Wireguard provider ($8/month for 1TB@100mbit). For that purpose one can spend half that for a VPS with gigabit speeds, even a quarter that during promotions. That provides the same services plus whatever else you can fit to it. What am I missing that they provide?