Searching for relatively cheap solutions for pneumatic wheels on direct drive motors

Hello, I’ve gotten myself one of these but I’ve run into a problem - with the 105mm wheels and 65mm motors the ground clearance is completely unfit for my terrain. Therefore I want to change out the wheels to ~20cm/8" pneumatics. I’ve seen a few mentions of people using some kind of cheap aliexpress 8" wheels for direct drive skateboards but never seen anything specific nor anything about how to actually mount them to direct drive motors. That’s why I’m asking for your help in finding a solution to this problem.

PS I’ve also got another related problem - the wheels are stuck onto the rear axle/direct drive mount. Do you have any tips for dislodging the wheels?