Modified sine wave inverters are more like square wave output, should be made illegal in my view, they are dangerous. full stop!
Many appliance will work with non sine wave inverters, many will die prematurely, some will even burst into flames!
If it has a motor
in it, it will die prematurely even if it works.
They are only really useful for simple resistive loads, capactivie loads will dislike them, inductive loads will positively hate them, each time the pulse goes on/off you will get a large back spike, a back emf which creates havoc in any inductive load.