Hello @tutti-insieme,
I recreated your table on my testing website https://sandbox.bunte-giraffe.de/test-the-table/ and it works fine for me.
The two things I found unsuitable for sorting were the non-breaking spaces before characters and some mixed order of tags like some cells have
text, other have
text, other
text. The non-breaking spaces are also counted as characters, so cells containing such spaces before actual characters will always be either first or last. As to the incoherent tags, it also puzzles our plugin.
I will also be sending you an email with the html code of your table without non-breaking characters and corrected tags order, so that you could try if it works for you.