Sorry for the tangent, but is anyone aware of any open source alternative to workflowy (quite a bit different to notion, a lot simpler, usually described as an infinite outliner)?

I really got on with that whilst I was briefly using it, but it being proprietary was a bit of a concern

Athens Research uses a workflowy like UI. It comes with a bunch of other features, but you can ignore those pretty easily.

Obsidian with the Outliner plugin is also nice - although Obsidian isn't open source, it is free and all your data is stored locally as markdown files.

1. https://github.com/athensresearch/athens

2. https://github.com/vslinko/obsidian-outliner