Will a RCBO 4P trip in case of neutral fault/failure/interrupt/float?
Unfortunately not.
An Residual Current Breaker trips only if the sum of the current on all four wires is nonzero. This residual current means there's a leak to earth, possibly through a human, and the breaker trips.

In your case, the loss of neutral meant the supplied voltages became unequal, some too high, but this won't make the total current nonzero.

There may be other devices which can protect you, but the basic RCB won't.