Stop watching CNN, it’s addled your thinking. None of those are even slightly realistic concerns. The only thing that can create a winning scenario for Democrats is enough election fraud to overturn a decisive pro-Trump result.
Fraud was a major part in 2018(and earlier) but the anti-Trump vote and sentiments were under-estimated in the run-up to the 2018 Mid-Terms...plus the historic premise that the party out of the White House gains seats in Congress...