I had looked into GRAV which is not quite suited for blogging (i.e. date-based posts) but rather for wiki-like content or a simple page structure. Also, they’re also feeling more and more enterprisey, especially with their recent 2.x release.

Tried Serendipity but found it to be more or less on life-support.

And finally settled on a very basic WordPress with only a handful of plugins (all set to auto-update), most importantly SQLite and ActivityPub. Backups are a simple copy of all the files or just the SQLite db. The Gutenberg post format in the SQLite db is easy enough to convert it to anything else using a small custom Python script should need be. I don’t remember how I imported my existing posts, though. Might’ve been via RSS import.