See the id field, it is the calculation I explained above. An important part is the format as text. See there is no delimiter, and comma is at the beginning. This is to get the correct index numbers. I have tested some more configurations. This one works.
Then, you can see the split by (This Text), get the first item, split by (,), count-1 (which are all explained above).
Maybe this can give some people inspiration and we can find a generic version of it without the limitation mentioned in the first sentence.
Thanks @hergin! Creative solution however lot’s of searches and might break with duplicate values. Probably simpler on the frontend to format a list of numbers as text referencing the original list within.
E.g. list of numbers:format as text — > id:this number, text: text(s)item#this number
Still don’t know what I can do on the backend though…