CVTs (generally) rely on belts sliding on cones. With more weight, you need more torque, with more torque you get more wear on the internal components. This is a big reason why CVTs have historically targeted smaller cars instead of larger trucks.

When it comes to motor reliability, generally speaking a smaller engine with higher compression running closer to its peak output all the time will have more wear than a slightly larger engine that doesn't have to run at as high of pressures and load percentage. Lower RPMs needed for the same power output means less friction on all the components in the motor. There's a lot of variances in that so it is not exactly a given.

These kind of go away with more modern "eCVTs" which don't rely on belts and hybrid systems which can help even out that peak engine load challenge. But still, turbos will generally reduce your reliability. More moving parts, higher pressures, etc. The questions are, will the increased efficiency balance out the reduced reliability and will the motor reliability be the thing that does the car in at the end.