[hocus pocus]

Maybe your phone is haunted. That is really weird. I'm not the tech-savvy one in our household but you made me think of something: how rural/populated is the area you live in?

It is pretty rural where I am and sometimes I have to leave the house to make a phone call or send a text message, especially if it is long or if I am trying to send in image. On rare occasions my mom or brother will get a text message 3+ hours later. Same happens for me. It just takes longer for it to go through.

Maybe something weird happened with it and you did type the message a long time ago but it didn't go through for a few months or something? I don't know if a message can be 'stuck' for that long or not. Maybe it could though? I mean, a lot of us have been home especially depending on where we live with the covid lockdowns and stuff.

Editing to say you might have a virus/malware which was the other thing that came to mind. Here's an FAQ that has a brief paragraph on it.