I purchased a new Lund in 2016 as well. I have the same problem as you. Please note that since these boats are painted, you do not need a specialized aluminum cleaner. Any boat or automotive paint cleaners or waxes will work. Just use caution if it is a “cleaner wax” as they usually have a light abrasive in them.
My boat is white on top with a gray bottom. I think most Lunds are gray on the bottom. The white paint and gunnels seem to be clear coated and water spots will come off at the car wash if I bring a sponge to do some manual labor. The gray on the bottom, however, is not clear coated and the water spots are a real pain to remove. As a matter of fact I’ve never completely done it.
The best thing I have found is Boat Bling Hot Sauce.
https://www.amazon.com/Boat-Bling-HS.../dp/B006GWVBQ8.
It will remove most of the spots and works great on everything above the water line as well. If you do a quick towel dry at the ramp and hit the problem areas with the Hot Sauce you’ll be doing pretty good.
Hope this helps.