You cannot ask everyone to use only the unaccented latin alphabet for names when there are EU countries that use other alphabets, and accents. And on the other

You cannot ask everyone to use only the unaccented latin alphabet for names when there are EU countries that use other alphabets, and accents. And on the other hand, you cannot ask people in the rest of the EU to learn cyrillic for when a Bulgarian citizen shows their pass. There is no easy solution for this, and including the native name + a normalised (ICAO 9303) version is probably the best one