Ok, thank you all for the input.
I have reworked my ui in luci javascipt. The interesting thing I found for my case is JSONMap.
I load data from a REST API and then generate a GridSection from the JSON. But when I click “edit”, I got the error: "RPCError: RPC call to uci/get failed with ubus code 4: Resource not found".
I seem to be missing something here, I tried to define the extedit property to no avail.
My understanding is that a uci-like structure is created in memory to render the table, is that possible that when the "edit" button is clicked in the table, the UI tries to fetch the data from a file (which would not exist)?
Is there a way to manipulate my data in memory and do a REST POST on the "save - apply" or do I absolutely need a file in “/etc/config”?
Thank you very much for your support