Add value in dropdown list linked to an external sheet

[David11]

Hi, I’m stuck with a new problem
It there a way to show a dropdown list linked to a google sheet document and be able to add values to this list when a new value is written ?
I tried data validity but did not work.
I tried ref / rel but it shows me a warning next to each item

(i have several dropdown lists to show, and for the moment i created one unique sheet with all the lists ; there are also associated values or descriptions for some items from the list )

Thank you !!