Yes, TxPID is to be tuned in rate mode. My understanding is still limited, but if I see right, you are tuning the so called inner loop there. This will affect attitude as well.
To use TxPID you need to fly the quad in rate mode, and make sure that you assigned the proper bank to that mode. Usually I use one flight mode for fixed attitude, one for fixed rate, and one for TxPID rate.