I need to use Joplin at two different jobs and also want to use it for private purposes. So what I need is the possibility to start three different instances of Joplin with three different storages and three different synchronisation settings.
At the moment I cannot find this feature and I do not know what to do, since no information from job A should appear at job B and vice versa.
You could use JoplinPortable, and run as many instances as you want, each one being independent. This is what I do myself, one for work in a folder namedJoplinWork, one for personnal use in a folder named JoplinPerso.
Thank you for this idea - but unfortunately there is no portable version for MacOS.
Since osx doesn't use a registry or similar, I wouldn't be surprised if you could just copy the app (container) from the applications folder to a stick and it were to work. I haven't tried with Joplin, but for a few other applications this works perfectly fine.
May be worth a try ?
Good idea - thank you!
I just tried it - but failed. MacOS claims "Program is damaged" and does not start it. 
Interesting, I am running Veracrypt in this "kind of portable" mode under Mojave, with no other moves or precautions, and it works just fine, not leaving a trace on the target system.
Joplin under Catalina is not so humble.
But it's possible with --profile, starting via a shell script. 