> Until support is well over 99%, using a custom port will mean your website is simply inaccessible to some visitors. Even worse, a link which works perfectly fine on one computer will simply be completely broken on another, without any kind of warning or explanation.

Welcome to my world. Some websites are blocked by my provider. Some websites are blocking my provider and inaccessible to me. And I'm not talking about something weird, things like w3c.com and istio.io were blocked at some periods of time for me.

You want a working Internet? You need to use VPN. I don't think that anyone will evade that.