Most welcome! Hope all is well in your world.
Having a system that works (easily) across devices is the highest of priorities on my list of must-haves as well. For the most part I’ve generally relied on solid desktop/laptop browser UI and struggled with mobile UI and bookmarklets or external tools to get things working reasonably. A recent workflow I’ve been working with: https://boffosocko.com/2020/08/29/a-note-taking-problem-and-a-proposed-solution/
I did quite like Wikity, but overall I think it would have been better built as a plugin rather than a theme. The concept of a Federated Wiki did work pretty well with it though. I imagine that it might be quite fun to have a Wikity with Webmentions enabled, but haven’t experimented here yet.
I’ve not played with PMWiki before, but it does look very nice. Most of my past experience has been with MediaWiki and DocuWiki which have been pleasant. I also like TiddlyWiki quite a bit, but it was a bit of an odyssey puzzling out how to get it online; I’m not quite sure how one might do a multi-user version, or even if it’s possible.
I keep meaning to create a list of more substantial personal online wikis (outside of the newer craze for digital gardens which tend to be more sparse), but here’s an awesome one I’ve found recently that I love for its size, complexity, and content: http://whitneyannetrettien.com/whiki/index.php