I must admit that one of the contrib modules that i always used to install with a drupal 7 website was the transliteration module. It's a life saver! So when i started building websites in drupal 8 i was like "Hey wait a minute, where is the transliteration module for drupal 8/9?"
Well here it is https://www.drupal.org/project/transliterate_filenames
Now there is a small change with this module. It only works for filenames. The old drupal 7 module works for urls too. But for me the biggest worry for using the transliteration module was to safely rename the "greek" or whatever file names in a utf-8 latin safe filename.