wifi speed fluctuations help

Recently we’ve had problems with our upload speed rapidly fluctuating between 5 - 40 Mbps. you can be playing a game for a few minutes with perfect response then boom, 450 ping for 30 seconds or so and then it goes back to normal. This happens about every 5 minutes or so. I have my console wired via ethernet and when testing the speed it does the same as if I were to use the app. the company came out today and repositioned the dish a little higher and installed a grounding rod as well, and while that improved the connection to a degree online gaming is still unplayable. Is there something I can do to get consistent connection?