You said 'significant'. Perhaps you could quantify that. Of course people from all voting brackets will vote all kinds of ways in some numbers, but the levels of support that Trump got to swing the rust belt in 2016 with his false promises to coal miners, etc, came from a small swing minority, which he then largely lost in 2020. Then there are the reasons people vote Republican that are peculiarly American and have little to do with income - eg religion, race, abortion rights. And there is the sharp divide between cities and rural areas, so you also need to define 'proletarian' here tbh, because traditionally this is a term used for urban industrial workers. Among that group, support for Trump is not big at all.