Tyres. Can you get solid tyres 20by 4

As in solid all the way through? You can use 16" motorcycle tires on your 20" ebike wheels. Are you sick of those soft balloon tires they all come with?
I'm just curious what you want solid tires for? Are you having lots of flats or other reasons?
Solid 20x4 tires would weigh something like 20 lbs each. If they existed. Which I am pretty sure they don't since the ride experience would be abominable. Just think of the kind of wheel construction you'd have to have.