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.
That's what I've gone for. I use Obsidian as an editor on Android. It's not ideal but the best I've found so far. On desktop I use Pulsar and sometimes micro.