I just found this article on how to create a basic ActivityPub server. It let's me think about adding ActivityPub support to my hugo-micropub project (which then becomes more than just a Micropub endpoint for my Hugo setup). It's definitely a project I finally want start once I'm done with this semester.
I still need to think about whether or not to ignore inbox queries and if yes, how to handle them? Can that also replace Pleroma and Microblog.pub for me?
And if I already integrate ActivityPub, I could also add support for accepting webmentions directly without the need of webmention.io…
It's like building a custom dynamic backend for the static Hugo CMS. It's not very useful, because I could just use WordPress with a couple of plugins, but it's definitely a lot of fun and includes a lot of learning new stuff.