AC protection terms can be confusing in mixed solar and storage BOMs. MCB, RCBO and RCCB devices solve different problems and should not be swapped only because the pole count looks similar.
The right device depends on overload protection, leakage protection, circuit grouping and local installation practice.
MCB protects against overcurrent
An MCB protects a circuit from overload and short circuit. It does not provide residual current protection by itself.
RCCB and RCBO handle residual current differently
An RCCB provides residual current protection for a group of circuits. An RCBO combines overcurrent and residual current protection in one device for an individual circuit.