I will just work with ensembles. They take forever in 5y Sims, but OOS I guess it will be more robust. Deterministic training on a handpicked "best" model might be too dangerous anyway.
Still, if somebody has info on how P123 is handling ML randomness at the backend, a I'd be interested to know. Any parameters outside the given set usually is ignored, so I assume that also goes for seeds if I'd put one in the hp json