The government being this sloppy at getting accents right is surprising, I would expect them to value accuracy and a clean paper trail when handling names.
Ascii is 7 bits. What people think of as 8-bit ASCII is actually code page 437, the alternate characters added to the PC BIOS in the original IBM PC. Like UTF-8 it uses the most significant bit in a 1 byte ASCII char to determine if it should use a character from ASCII if 0 or the extended 437 characters which includes ü if 1. https://en.wikipedia.org/wiki/Code_page_437
0. https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-...
Answering your question - basically, this comes down to the traditions of the languages.
https://ru.wikipedia.org/wiki/Макконахи,_Мэттью
https://uk.wikipedia.org/wiki/Метью_Макконагі
https://bg.wikipedia.org/wiki/Матю_Макконъхи
https://www.joe.ie/news/garda-spent-two-years-searching-for-...
Obligatory read: https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-...
It can go the other extreme too of course: https://www.stuff.co.nz/nz-news/360848808/worlds-longest-nam...