Overwhelming = under 25% of the US population that voted for him in 2016? Even among registered voters only it's still under 50% - how is that overwhelming?
Big citation needed on who of non-voters support Trump. Most opinion polls that include anyone (not just registered voters) still have Trump's approval at 40ish percent the past 4 years.
If you say all polling is invalid/not representative, where are you getting your numbers from?
his base is tiny. he was only elected because he had a base, plus a lot of republicans held their noses and voted for him. His true base is getting smaller every day; I have a bunch of friends in the midwest and many of them have reported that even the folks they knew who were huge Trump supporters have decided he's crossed too many lines (specifically, disrespecting the military, the covid press briefings, attacking people unnecessarily, and not actually helping working people) and plan to simply not vote in the presidential election (rather than voting for biden). I was struck at how many of my friends reported this rapid shift over the past few months.