File tags are not changed

Hello! In your program, I completely deleted the tags of several music files "mp3" using the group method with the "red cross" button, including "Cover", then using the group method, I recorded the tags "Album", "Artist", Title" from the file name in the ID3v2.3 UTF-16 format, entered "Genre", these music files were recorded on a USB flash card, but when playing it in the car in Subaru Starlink 2019, I saw that some files still had covers, some did not change the tags "Album", Genre", and in some cases, instead of the tags "Artist", rectangles are shown. Can you tell me how to fix this? If this issue has already been discussed, please provide a link.

What kind of files are these? Flac? MP3? Mp4?
You would have to make sure that there are really no more tags in the files which means that you have to read, write an delete all tag versions. See
and tick all tag versions.
You would have to check that there are no stray images in the folders.
You would have to make sure that the player does not load any data from the internet.
You would have to clear any player-internal database or update it.

Hello! I wrote that the files are "mp3". After several attempts through your program, I completely removed all the tags, but after extracting the tags from the file names (the same ones that showed the error before), the artist names are again "rectangles".

Does MP3tag show the data as it should be?
If so, you have to investigate why your car player behaves like that.
E.g. do you see the rectangles on each track or just some with non-ASCII characters?
Perhaps this thread helps: