Sure I can try to translate the essence my ubiquitous error-messages (there are quite long and intimidating, you know).

Thanks, your explanations clarifies things for me.

May I ask: Could you put the formula in an xlsx, because this way the English formulas translate to German. I can translate IFERROR etc. by myself, but Excel does not recognizes "MATCH". And could you do this for at least to columns. This way I probably can expand it to more columns myself.

This problem with unique entries, that will get "even more complicated". In fact there will be dozens of words. Do you thing, this is manageable in that way?

And (of course) I have another question: How can I compact a list of numbers. At the end I do not want "21, 22, 23, 24, 25" (for example), but "21-25", "34, 35" changed to "34f" and "56, 57, 58" changed to "56ff"

No problems with ";". Everything is fine.