I have a very difficult time tagging with MC 21 or its recent ancestors, for this same reason. What slows me down are the limited lists, variable ways to work with them, and the persistent requirement to Search when I already know exactly what I want, I just need scroll or even better jump to it, and Select. And to keep working in the same list, multiple values, until I'm finished with that field.
Maybe my library is unusual, but it is the reason I adopted MC/MJ many years ago. I use many custom fields. Many of my fields have many, many values. Many of my fields are list/multi-value type. That's what works for me, to do radio-station type tagging of almost 70 thousand tracks. But it's just so clumsy and slow in today's MC.
Therefore, along with the newest MC (21 now, but already paid for MC22), I also run MC15.0.122. This was the last version that provided direct, keyboard efficient, lightning-fast Jump among values and Select via-checkbox tagging.
This was how MC had worked for many years. But the very next MC15 build removed this mode, replacing it with the current Search mode. At that time I suggested (begged) that the Search mode be an additional method, not a total replacement of the Select mode. Ideally, they would both be available, perhaps as a global user option, or a live choice (such as, press F2 to tag via Select, Ctrl+F2 to tag via Search).
I'm not being stubborn. Every time a new MC build arrives, in my music library I re-try tagging, get frustrated with all the Search and extra steps, and switch back to MC15.0.122.
But, I have a bit more success with Search when tagging my photos library, because it is much simpler. Just the date-time, Caption, Keywords, and no custom fields. So it has its place, and I value (and keep paying for) other MC improvements. (Though even tagging photos would be easier in an MC with Select mode.)
Again, please bring back the method used in early MC15 and prior versions.