To add something constructive, most of the forecasts are done using polling data (with some fundamentals). Polls being inaccurate are a legitimate critique for the forecasts - so what you can do is to adjust the polls using you think are the correct numbers.
For example, if you think the polls overcount Biden voters (or miscount shy voters), you can adjust Biden's numbers by X percent, and if you think all the undecided voters will vote Republican, you can adjust the models by assigning 100% of those voters to Trump (compared to the 50-60% that most models currently do).
You can do all of the above at both a national and state-wide level to come up with your own forecast.
If you are lazy, you can just use
www.270towin.com. One path to victory for Trump is to win Pennsylvania (in addition to AZ, OH, NC, GA, FL).
BOL