Biden was dealing with the death of his son from cancer in the season leading up to the primaries and didn’t compete in 2016. Your assertion that Trump > Clinton > Biden falls on its face. The only time Biden ever went head to head with Trump he won. Primary season is over and with an incumbent you and I pretty much knew it was over before it started. Third parties can’t win and for practical purposes parties are unlikely to change horses with an incumbent and actually win elections. Yes winning elections vs allowing the other side to elect a genocidal fascist is an overriding concern because of course it is. This go round was always going to be Trump v Biden v2. If we go with Biden we get slow change and investment in America. If we go with Trump he gets 4 years to try to destroy democracy and our country at best crashes as he guts the government in a way that takes us 10 years to recover from while millions of Taiwanese and Ukrainians die. At worst we fight a civil war to restore democracy like Spain too.
If you want to really reform the way we do elections you can’t do it by bitching on lemmy. The most achievable changes are ranked choice voting in primaries and general in the states. That is something the states can legally do. The next most achievable is getting rid of the filibuster in the senate followed by expanding the supreme court. Even though this really only requires a simple majority it probably practically requires 55 in the senate.
We can start on these reforms that Republicans oppose vehemently by voting for Biden in the coming election and democrats down ballot while pushing for these reforms at home. In my state—Washington—we have an initiative process. Maybe they do in your state too.