Yes one way you can test that is bit tricky. You have to lift up both wheels out of ground , donāt forget safety matters must use proper jack stand. Put shift to D and accelerate until speedometer touched al least 80km/h keep steady and monitoring your engine rpm tachometer reading and note down , now have drive on road if you give full trust to meet 80 speed quickly and when reach check your rpm on this stage , if you found rpm greater than without load , itās mean someone is bad cvt belt slipping , thatās my personality suggestion for test, if any tool available I donāt have idea .