Pretty much any static page created with Hugo will work. There are some really nice blogging themes/templates for it. RSS is included, but for comments you will need some external software.

(Self hosted) Wordpress is a classic choice. There is even an ActivityPub plugin.

Some alternatives to writefreely:

• Bear Blog
• Mataora
• rwtxt
• Diary.by ^(new)

Thanks for all your help, I’ve settled on Mataroa

You could use a static page (I recommend Zola instead of Hugo), or you could simply use Write.as. Both are great options!