This is just a simple example how Live Play can work.
I made this for another post but it is applicable here:

Here's a play direct vst, just unzip and drag song.sfz into Sforzando VST or Standalone.
This is playing compressed mp3 sections on demand from different bars in the mp3 file. Hold a key down then move to another key. It will loop 4 bars of the chord when you hold a key down.
This is the same way the BBPlugin can play back wma/m4a direct.

song.zip

Sforzando can use wav, aiff, ogg, mp3 it was made by dropping the Biab song into Reaper and set the time display to Samples so you can set the start-end sample time for the sections in the sfz opened in Notepad, make sure your Reaper session is set to 44100 to get correct samples.

I could make one right now with actual chord input that will go to that chord section as you input that chord, change on next beat or bar and latch so you only need to press the chord and let go and it will keep looping that section until you play another chord, but I would rather see PG do it using the BBPlugin Standalone.

https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)
Open SGU in Reaper Instantly