Zettlr can recognize Logseq pages and tags
I primarily use Zettlr and rely on its hierarchical structuring capabilities but I've realized that some of my personal note-taking/idea generating processes might be facilitated through Logseq's unstructured workflow (particularly when they're quick/simple atomic notes). However, I didn't want to have separate sets of notes and neither tool overlaps completely with the other. I'm posting this here in case it's useful to anyone else.
I found that I can make Logseq and Zettlr interoperate a bit by including
id: YYMMDDhhmmss as a YAML property within Logseq notes. Logseq does not do this automatically (I need to type it into the note).
Then I added my Logseq folder as a Zettlr workspace and Zettlr automatically recognizes those IDs just like normal. This allows me to link within Zettlr notes to a note made in Logseq. Zettlr also recognizes the tags from Logseq and includes them in its tag cloud or searches just like normal.
The reverse is not true of course. If I create something in Zettlr it won't automatically be findable in Logseq but at the moment this works well for the way I want to work. I like using Logseq for an unstructured flow of ideas/notes, etc. I like using Zettlr to expand on ideas more, for formatting, and for its hierarchical functionality. This way, I can begin certain notes in Logseq and develop or organize them further in Zettlr.
P.S. I promise that I have not made any requests to put Logseq code into Zettlr :-)