If you’re looking to squat heavy but don’t have the room for a dedicated rack, you can use weights such as double kettlebells or double dumbbells in order to mimic the evenly distributed weight of a bar.
As the weights are forward-facing as opposed to sitting at the top of your back, you’ll also get much more of a quad-focused workout with lighter weights, so it’s not the end of the world if you don’t have the room for a squat rack!