On the bottom of RT picker you can filter quite a few things, but the process is a bit unintuitive and not sequential.
I believe you have some valid points here most were brought up before. I strongly support sorting by Instrument Family type (guitar, piano, harmonica etc) That, in my view should be #1 column in the picker which would double as filter. Because in 99% of cases you already have an idea of what type of instrument you will be selecting.
A lot of people mention that, but BIAB hasn't changed anything, has it?
It's very important to me that we go by instrument.
Because I don't know English at all. I only know the words guitar, piano,Bass.
If I needed another instrument, I wouldn't know how to spell it.
A harmonica? How to spell, I first go to the dictionary to see if it is correct, then RT search, very troublesome.

RT is an important core of BIAB.
Some very searchable features should be added.