I made the previous post using my phone.
It’s annoying that I can’t use the WordPress app with self-hosted sites (which is what this is), but the “mobile web” experience for the same is not too bad.
I can’t write in that web interface, for whatever reason, but that’s okay as long as I can copy-paste in content.
I use Drafts heavily now on my phone, which works very well as a “staging point” for all text.
So, writing there and then using the mobile web to just add it in, and click “publish” works for me.