An observation regarding Tag values and Performance Speeds

[RobNeptune]

Environment:
Windows 11/64bit OS, 64GB RAM
MP3Tag version is 3.21,64bit
All files are stored locally on an external drive connected via USB3.1
[Western Digital 10TB WD Gold Enterprise Class Internal Hard Drive - 7200 RPM Class, SATA 6 Gb/s, 256 MB Cache, 3.5" - WD102KRYZ]

Observations:
I am using MP3Tag to curate a large number of video files of BR/DVD movies that I have converted to MP4 format, and are typically pretty large (2GB to 10GB). While editing the metatags in MP3Tag, I noticed that SOME meta edits (for example, editing the Title field) were completed very quickly, but the same type of edits to other video files took up to 5 minutes to complete even a simple/single meta edit.
Eventually, I realized the FAST edits were always on files in which the Tag field was defined (Tag="MP4 (MP4)"). However, if the Tag field was empty or null, the edit would always take several (>5?) minutes to complete.
Interestingly, I noticed that once the Title field was defined, MP3Tag seems to have automatically defined the tag field as well to be Tag="MP4 (MP4)". Once the Tag field was defined, subsequent meta edits and updates completed at lightning speeds.

Questions:

1. Is there any way to automatically predefine MP4 file "Tag" fields with "MP4 (MP4)"?
2. If the answer to the above is no, I would welcome any advice to achieve the same goal outside of MP3Tag via script or powershell?
3. Is there any way to accelerate the existing "first tag edit" process?
4. If I copy video files to/from my WD Hard Drive, I typically see speeds around 180Mbps, but Task Manager indicates that the transfer rate between MP3Tag and my drive is rarely more than half that speed. Is there anything that can be enhanced within MP3Tag to increase the number of threads?

[ohrenkino]

If there has not been any tag data in a file, the tag data has to be added and the file rewritten.
When a tag is added to a file, it is usually added with some padding. So that if subsequent edits do not exceed the size of the padding, then the file does not have to be rewritten but the changes can simply be inserted in the available space.
So if your conversion program would add space for tag data then MP3tag would not have to take care of that.

As USB is a serial bus, more threads will not speed up things as the bottleneck is the serial access to the device. You could test that with 2 of the large files and copy them with 2 copy jobs to the usb drive - you will see that the transfer rate will be shared between the 2 files.