I painted my concrete basement floor as part of a finished basement reno about 10 yrs ago. I used self leveler concrete to smooth out shallow dips and a spot where we cut the slab to move a pipe. For final finish before paint I rented a floor grinder and went over the entire surface to smooth out the small features and prep it to take the paint. Its a very dusty process but might be a better way to prep your floor and get rid of the paint simultaneously.

I recommend carpet tiles from flor.com, I used them to carpet a basement bedroom. They are not dirt cheap, but you can find good deals in sale. They are very durable, come with a built in underlay that is waterproof and has grip. When you’re done with them in your temporary space you could use them in a different part of your house. They cut really easily and install with stickers that link tiles together.