That's what I started with originally, but it's not offline and stores all data on their servers. Something like Workflowy but offline or self-hosted would be brilliant.

Workflowy's never-ending delays for an API make Logseq look fast.

Truth is, it's been nearly a decade since I used Workflowy and nothing has ever been as good. But the inability to email notes to it or otherwise push data to it from other sources was such a deal breaker. Particularly as mobile became a larger and larger part of my life.

Then there was Moo.do, the next best infinite-outline tool I could find. Their rebrand as Legend was strange, made it hard to find the app, and, from an SEO perspective, was an odd choice.

One of these days I should return to either Workflowy or Legend. My issues were silly and now are much more surmountable.

EDIT: WOW, Workflowy has really gotten with the times! Seems to be iterating much faster and even has an MCP server.

Workflowy is not free. If you are willing to pay, Obsidian > Workflowy. If you are not willing to pay, Obsidian > Workflowy.