The trinity is in the Bible. Not the word “trinity”, but our understanding of it comes purely from the Bible. Which is why even most SDAs agree with it. Real presence (part of the doctrine of transubstantiation) and miracles are also biblical. The New World Translation of the Holy Scriptures and the Book of Mormon, Doctrine and Covenants and the Pearl of Great Price aren’t biblical. Just like how the Qur’an isn’t biblical.
Muslim means “one who submits”, so I could identify as a muslim even though I don’t even adhere to Islam- it doesn’t make me Muslim.
If you want to self host with FOSS, you could try something with good ol’ Wordpress. It also carries the bonus of apparently being able to federate (I never got this working ☹️)