The thing is that there already is a very good self-hosted option for sync - Livesync. I won't say it's not eccentric and confusing (it is!) but once you get it to work, it actually works extremely well and is lightning fast too. I use syncthing as well for backups but livesync has the obvious advantage of working natively inside Obsidian.

I'm so done with subscriptions for cloud based solutions and between livesync and syncthing, you've got a very robust set of options to use.

iCloud sync actually messed up every file I opened due to the lag between remote copy and local edits. iCloud would delete the last few edits whether I was in the file or after closing the file. Sometimes I would be typing something and I'd watch it delete what I just typed. It was a complete disaster.