ACX check ... when I fix the Peak I unfix the RMS!!!

Translation: they’re complaining conspicuous amounts of noise-reduction and/or noise-gate have been used.
i.e. noise-gate is the disease, not the cure, for that complaint.

Possibly there is a noise-gate operating by default somewhere when you record, (not in Audcaity).

Limiting (without make-up gain) will inevitably reduce the RMS somewhat,
so RMS normalize +1 or +2 dB higher than your target, then apply the limiter.