I’ve used tank sprayers for fertilizer, weeds, flowers, bugs, winter deicer, deck and aluminum siding cleaning and to finish.
Tank sprayers are easy, versatile, convenient, repairable, sizes 2 pints, 1 gallon, 2 gallons, cost $15 – $50.
There are good ones. Don’t look by price, shop for good brands because you can use it for projects in all seasons for many years.