Keep frame sequence numbers monotonic, lock the RDS carrier to the exact pilot phase used by the stereo encoder, and apply the accompanying DSP/control cleanups needed for stable live transmission behaviour.
Keep DSP state persistent across generated frames, move the RDS encoder to arbitrary sample-rate operation, and tune the Pluto profile to the working 2.28 MHz path with the levels that finally decode reliably.
Replace the pilot-derived RDS path with a PiFmRds-style 228 kHz shaped biphase generator, resample it into the composite loop, and retune Pluto example levels plus spectral thresholds around the new RDS behaviour.
Drive RDS in the offline/MPX path from the pilot-locked 57 kHz carrier with biphase symbol timing, and adjust Pluto example levels plus spectral thresholds for the new multiplex behaviour.