Change the rcd of the distribution box to a HI(high immunity) version.

If you don’t know what or how to do it, engage a professional. Don’t diy if you don’t know what you are doing. Can be very dangerous.

The reason a residual current device trips is because of imbalance current between the live/neutral.  By right it must balance. Same current flow out of live must return thru the neutral.

For example 1ampere goes out thru the live wire and 0.95ampere returns from the neutral. An 100mA(0.1) RCD will trip every time.

So if your RCD is tripping say 100mA rated trip it means it detects 0.1Amp imbalance between the live and neutral. Your wires have bad insulation. Either too old, damaged or a bad connection in one of the circuits.

I can probably pinpoint any faulty circuit within 10minutes at the DB and isolate what is wrong. It isn't that hard.

Back on topic to resolve your problem you need to check if you have bad wiring insulation or if your unit at a high elevation and lightning is affecting your wiring. So either repair the bad insulation wires or install lightning rods or surge protection.

The easiest is to repair the bad wiring insulation.