>>2919343 (OP)if you want to put in the hard work, wet the walls with a spray bottle, wait for it to soak into the wall a little, and then scrape it off. It's going to take a while ngl. It will make a mess on the carpet unless you put down something to catch the debris with. Use a plastic sheet and tape it (using BLUE painters tape; NOT WHITE masking tape) to the white board that runs along the bottom of the wall. This shit is heavy, so don't fill up the garbage back to the top. Go like, 1/3 to 1/2 of the way. Also, you don't know what that shit is composed of, so wear at least a N95 mask. A 3M respirator is a good long-term investment for your lungs. The ceiling looks adequate, so don't change it.
As for the carpeting, it was installed like shit. It was laid out and tucked in, but it clearly wasn't stretched into place. Get a knee-kick tool to stretch the fabric flat. You'll need to cut off the excess (probably a couple inches) with a knife. There's a strip that looks like a piece of wood with nails/staples in it and flipped upside down so the spikes point up. It's under the carpet along the edges of the room that keeps it taut. Do not remove them.
Anyway, that's all I care to type for now. Utilize youtube for more details.