@DBDigital is correct. The lowest value takes precedence. I only said to set the history to 2 days on all devices so that any device would pick up the cleaning job.
Also, it used to be possible to set the history to 0 days on desktop, but that has since been disallowed, though the existing setting wont change if it is already set to 0.
Well some devices can’t use the latest version. And to do all that I might as well clear the sync target, upload, and resync all devices again. It would likely be faster anyway.
If you want the note history cleaning to work properly, you’ll need to upgrade to Joplin 3.4.x on at least one of your clients (on older versions, even though you see the revision deletions when you sync, they will get redownloaded again). Otherwise the history will keep on increasing over time, even if you start from a blank slate. I can’t guarantee your other Joplin clients would be compatible though if you mix and match versions.
If upgrading is not an option and you’re ok to forfeit the use of note history at all, you could do a full reset ( How to fix synchronisation issues and start over ) to clear all revisions (this works because a jex export does not backup the revisions) and then disable the enable note history setting on all clients.