If you just count moving parts, a piston engine has more moving parts than a turbine engine, and both have more moving parts than an electric motor. And an electric motor is basically a large starter motor, which both a piston and turbine engine include as an accessory, so by default, both would have more parts than an electric engine on its own.
But physical complexity of the power plant isn’t the whole story. When you add in the software (FADEC, etc) that controls the entire system, all three can be similarly complex. It’s just a matter of where the likely failure points will be that is different. And it sounds like from above that it might not necessarily be a mechanical failure that caused this incident.