So two things
Activity pub is federation. So you'd be publishing to anywhere. Which as I said before, ghost is actively working on. They have a weekly mailer.
If your looking for an algorithm publishing centre, your going to find open source to be lacking. Generally speaking people who are looking for open source, don't want the algorithmic feeding that your describing.
Started my transition 2021 (holy fuck that was a long time ago?!)
There is no right answer, nor does your answer have to stay the same.
There's a lot of processing that comes with this. I wouldn't recommend burning photos, but maybe putting them in a box where you no longer remember they exist.
I started wanting to burn it all, but I find myself wanting to show that pretransition me live, rather that disgust now days. It's still me, it's still made me who I am, but just like I'm no longer 14 year old me either, I'm no longer that person.