Dopamine is certainly important, but the whole system (the human body) is so complex I don't think we know how to correct some of these imbalances for sure yet.
The points you make all seem at least possible to me, so they can at least give us ideas to try out. Try something and see if it helps, try something else and see if it helps, etc.
For example there is a "dopamine diet" book which aims to help weight loss by using foods which encourage dopamine creation. Your edit 3 also seems like an interesting idea to me, but in the opposite direction, maybe some kind of "dopamine fast" to try and remove excess receptors could be a way forward rather than trying to get more dopamine to fill up the receptors.
ì reversed my type 2 diabetes in no small part down to the recipes in Tom Kerridge's Dopamine diet.