Thinking about it again - I left out some things that might make your two-list solution not work fully for my use case
I want the users not only to be able to add values to a key:value relation but also to be able to edit or delete these values
This might makes it complicated using the two lists solution because it would be rather complicated to edit/delete a value based on their list location
I know there are workarounds that can manage that but I think that might be not ideal for this use case
I think the ideal solution should enable me to be able to find a specific value according to it’s key and not the list’s location
Any ideas on how to implement something of that sort?