Remember when everyone was convinced Copmala was the DNC's chosen one after she bodied Biden at the first or second debate? Those were the days. It looked like Biden was going to be a fallman for someone. Instead everyone else was a fallman for him.
I think she was probably the original pick until Tulsi killed her momentum in a single night. That is probably why the DNC went so hard against the Surf Mom afterwards.
Biden's ascendancy was basically the political equivalent of a worked shoot, the Plan B to put into place if Kamala faltered too quickly. Even with COVID-19 effectively ceasing the primaries for the time being, it's pretty obvious that Biden will be the nominee for 2020.
Bernie's presidential run is only existing on paper at this point and Biden is the de facto DNC pick for 2020. The real question now is who will be his VP and how much will the pandemic affect the outcome of the election?
Now that the relief bill is mostly a done deal, I think Trump will have it in the bag if things can recover enough for the restrictions to be lifted by the end of the summer.
Realistically, the best-case scenario will be one where Trump and the federal government is able to loosen the most dire of the national restrictions and emergency measures by the first week of May outside of the worst-hit places like New York and California, and then slowly but steadily relax those conditions throughout the summer.
If things improve just enough for the bulk of the isolation and shutdown measures can be ended before Mother's Day 2020, then Trump will have this in the bag. The middle of May is probably the latest that the majority of the populace can tolerate these isolation conditions before many of them start to snap or grow extremely disgruntled, and the earlier these measures can be safely lifted, the better.