Carnet - Suggestion how to use simultaneously

I’m looking for a comfortable shopping list app on nextcloud, where my wife and me can use the same list simultaneously. But until now I found nothing fitting perfectly. The best tool from my point of view is Carnet, but I don’t suceed to run it as a “shared service”.

I’d like to use Carnet/the shopping list with my wife especially via phone simoultaneously. Last time I tried to get the “Carnet” folder in a shared folder with my wife and thought, this might bis sufficient. But it didn’t work and produced errors, didn’t sync really.

Is it possible to use Carnet in the way I’d like to or should I stop my trials because it can’t work? If it is possible, could someone describe how to do it?

Thanks in adavance!

I have an idea for a solution: It’s possible, just to log in on my phone not with my NC app but with user credintionals. So it should be possible to log in with the credentials of my wife and in that way having Carnet synced. Theoretcally. In fact, for this alternative login method there is written, that it isn’t working on all servers. I tried it with an app password and with the “original” user credintials. In both ways I’m able to log in. But the notices from Carnet on NC already written aren’t syncing on my phone.

Anybody any idea?!