Trump will probably be re-elected as the next president regardless of the outcome of these trials. That is the truth that the Democratic Party refuses to see. The legal system is being used to circomvent electoral process. Everyone sees that, including Democrats. The trials are show trials and will not affect the election. There is nothing really there.
Thinking that re-running a Biden/Harris ticket as the only alternative, that is really a bad move. Any other viable Democratic challenger would win easily.
In the immortal words of James Carville; “It is the economy, stupid!” And the boarder (which is about the Economy) and foreign aid (also about the Economy).
People vote with their pocketbooks.