Does your ISP allow you to host your own server for a small website without paying for a commercial plan? I recently moved and my new ISP doesn't allow the port to be open.
This is one of many reasons to prefer smaller regional ISPs over the cable monopolists: the cable monopolists only want you to be an end-user staring at videos and clicking on cat pictures all day — not building new things like a Lemmy instance.
For instance, here in the Bay Area, regional ISPs like Sonic.net and Monkeybrains are friendly to hobbyist servers, while Comcast/Xfinity is very much not.
Unfortunately, there are a lot of places where the cable monopolist is the only straightforward option.