If you have the technical ability to create an app, you probably have the ability to upload something to /.well-known/ or to add a DNS TXT record.
That way the Snap store could say "This app came from this website."
OK, it doesn't help if someone goes to the trouble of registering a homograph address, but it would at least give normal users a chance to check out who the author is.
That seems to be how Flathub works. It shows a verified domain, or prominently says that it is a community released app.