Borates vs Salt

[chem geek]

so how would borates work as a PH buffer in a pool with a high TA/PH fill source, especially with a very high evaporation/refill rate?

The borates still act as a pH buffer, but your evaporation and refill will still have the TA rise, though the pH won't move up as much as before. You'd still possibly be adding about as much acid so it just makes it so you don't have to add acid as often.