MP3Tag Slow to launch

I added a bit too many tag entries with the MP3Tag program. As a result, the program starts slowly. It seems wrong to me that the tag editing program starts slowly because there are too many tags. What do you think?

I doubt that this is the cause.

I think you should start with letting us know how many songs you load into Mp3tag?
What kind of music format is that? mp3? FLAC?
Where is this music stored? Locally, on a USB-Drive? On a NAS?

Does it launch slowly with only 10 tracks too?

And last but not least:
What is "slow" for you? 3 Seconds? 30 Seconds? 3 Minutes?

Does the program start slowly or does the load-process of your files take much time?
There is no need to start MP3Tag and load all your files at startup.

I didn't count how many labels there are, so many. I like to add all kinds of information like Photographer, Producer, Media person.

1.) With Mp3tag I organize sometimes 10 and sometimes 50 music.
2.) Mostly FLAC but sometimes I edit MP3 music.
3.) I store music locally (M2 SSD)
4.) The program opens slowly for about 5-10 seconds and also slows down when reading the tags when switching to other music.

I am using a remote computer with high hardware specs.

The program opens slowly for about 5-10 seconds and also slows down when reading tags when switching to other music.

I am not quite sure what that means.
In general: I do not think that

is slow.
How long does it take other programs to deal with new files?
E.g. how long does it take the windows explorer to display the thumbnails of a folder with new pictures?

If you want to speed up the loading of old folders, then switch on the library function. Even though intended for something else, the faster loading of already known files is a welcome by-product.