As I proposed previously, all they could do (unlikely, and unrealistic) was bring back Ncuti for a proper regeneration special where Gatwa suffers from a unique situation where he regenerates into former companions of his and back, allowing thus to bring back his recent companions as a twentieth anniversary treat but acting as the Doctor for once. In this way, Piper's involvement would be the most minimal possible. And at the end of the special, Gatwa would resolve the situation and regenerate properly into the next Doctor.
Speaking of which, there's absolutely no discussion whatsoever on who the next Doctor will be?