They can be done, but only under certain circumstances. For example, you should never do a superset of workouts that target the same area. You can target different areas in a superset, and this would be more like cross-training.
When starting a gym in your garage, you must consider getting all these essentials. However, if you don’t have the budget to invest all at once, you can always start with some essential equipment and add more to your gym later.
Although the main principle of all dip exercises is the same, to keep the focus on the chest, you have to make the correct posture. To do that, hoist your body and lean your torso towards the front. Angle the elbows outwards from the torso.