Ugly garage walls, need help

You could attach used wood flooring to the walls?

sheet rock has its place. It’s reall hard to burn. The paper may burn the rock part doesn’t. In case of a fire, it’s what you want for the walls. Taping and mudding isn’t a hard task. It just takes practice. You can get the supplies at big box diy, some give a how to do course. The edges of the dry wall a slightly beveled so with the tape over the seam and the mud it will be level with the rest of sheet rock. The screws should be counter sunk in to the dry wall and mudded over. it might take a few coats as the mud dries an shrinks a bit. The spraying on of the wall texture...that’s a bit more complicated. It requires a certain equipment also rentable..it’s a hand held hopper and compressed air shoots a certain mix of a dry wall compound on the wall. Again, it’s a let it dry completely thing. Then prime and paint.