Operation speed + blurred display

1
One hour of 92kHz/24 bit (2GB of data) stereo track.
Splitting a stereo track into two separate tracks - without delay.
Turning back to stereo track:
i5-3210M Win7 8GB RAM Audacity 2.4.2 - no lag.
i7-13620H Win11 16GB RAM Audacity 3.5.1 - 11 neverendig seconds !!!
I assume that the work with tracks inside the program has changed, which unfortunately affected compatibility with older .aup and slowed some things down a lot when using new versions of Audacity.
Is it possible for me to set something somewhere as a user to speed up the work of the new version program?

2
I have a small 15.6" 1920x1080 screen.
It would be possible to add to the Audacity program support for the normal zoom of 125% within the Windows aby nebyl romazaný obraz?
For audacity.exe, I set that the Audacity program will adjust the resolution - the image is no longer blurred (now is pixel to pixel).
So many things fit on the display, but these are very small.

3 For interest.
It is possible to have both versions together on Win11 same computer:
Adacity 2.4.2 with ffmpeg 2.2.2 (file location: program files2)
Audacity 3.5.1. with ffmpeg 5.0.0 (file location: program files)
Unfortunately, I haven’t found a way to force each version to have a different location for temporary files. But maybe this is not the only reason why the setup of one version is deleted every time when the other version is started.
Maybe someone knows a solution.