Ironically, if Obsidian was open source and charged $25/mo for services, I'd happily pay for it. Even if they used a strict license to deter competitors (eg. stating they must license their changes back to Obsidian and that all hosted software interacting with Obsidian must also be open source).
Workflow: PKM in Obsidian, move ready docs to designated docs folder tree, sync w/ git to shared docs site repo, two-way collaborate w/ colleagues on docs.
You do need to align some options in each, such as file naming, a header, a particular style of links, and ensure frontmatter behavior. All necessary settings exist.
https://foambubble.github.io/foam/
https://github.com/foambubble/foam/issues/46
This supports basic static file and links functionality, not extended data tools etc., of course.
For me that was actually the reason I switched to it - I usually take notes in the form of deeply nested lists, which isn't as ergonomic in normal note-taking tools (the Obsidian plugins for it are not enough).