I think my whitelisted relay works on web clients now. It seems that the issue was because I'm running the relay without TLS [1].
I've been using the basic relayer implementation from fiatjaf since it's the only thing that I can reasonably understand and I don't think any of the relay implementations that use docker magic will work on OpenBSD. Also, the lack of documentation on doing this in an OpenBSD server makes it a little more challenging.
It's all good now though, I think.