You may turn out to be right, but there is more than a fair chance it will be a squeaker either way. Your key assertion about polling doesn’t stand up to scrutiny when you look at swing states. The RCP averages show Trump is doing better against Biden than he was doing against Hillary in Florida, Minnesota, Michigan, North Carolina, Pennsylvania, and Wisconsin. True, he is still behind in all those states, but if he beats the poll averages by the same margins as last time, he will be over 270 by a comfortable margin.
You keep talking about improvements made in polling techniques. Could you describe a few?
Finally, the turnout on election day will be predominantly for Trump. There is a record count of absentees, early votes, and mail-ins. Who really knows how big the total turnout will be? There is a huge enthusiasm gap and Democrats have decided to put minimal effort into their election day ground game. There is more than an even shot nominal Biden voters don’t show up in sufficient numbers on election day. Then the counting of the mail-ins and early votes will take days. Lots of ballots will be challenged, lots of suits will be filed, and more than a few frauds will be uncovered. All this means we won’t know who won for a while. The Supreme Court may have to issue Bush v Gore rulings in ten states. Some states may not be done counting by the date when they have to certify their electors. There may be urban unrest including violent demonstrations outside polling stations.
I have no idea how to mix in all these possibilities to arrive at a prediction and to have as much confidence in it as you have in yours.