Up to now I've been using Simplenote, which has a Linux client (but also Android & iOS) & supports live collaboration on notes. However, Simplenote hasn't had a meaningful update for a long time, & it's recently been behaving strangely, e.g. notes undeleting themselves, line duplications & undeletions.
Can anyone recommend an alternative? Spinning up an ownCloud/nextcloud instance just to use Joplin feels a little overkill. I stumbled across turtl, but the project looks abandoned.
I've used vim with a smattering of essential plugins for years to do this, and only this year moved to Neovim for the same.
It's not Open Source, but I've also taken a hefty liking to Obsidian's canvas mode. Likewise, I share a small selection of lists with my other half via Google Keep.