just matchmake in the multiplayer mode, you can choose unranked so it won't affect your ranking?
or there are custom maps called 1v1 obs (map name here) that can help you practice without leaving any win-loss records on your profile if that's what you're worried about
the best way to improve is to play people better than you, and watch the replays to see why you lost lol
or you can vs ai. they're fun to play too, and the new co-op mode, is a nice intro as well