I have noticed similar issues.
I reverted to 12.6, as said in this thread, because 12.7 was sluggish from launch.
I noticed that 12.6 would eventually become sluggish too, after some time (> 1 day).
I tried 12.7 again, this time it wasn't sluggish from launch, but became after some time too (> 1 day).
I made tests with all shell extension disabled, but it made no difference.