It doesn’t matter whom you or I think can best take on Trump. This is going to be purely a turnout race between the 60% better angel of America and the nation’s 40% misfits, not a personal tug of war between Trump and whomever the Democrats nominate.
First off you know that Trump is going to get most of the his 40% to turn out. It therefore comes down to how many of the 60% of the good guys turn out, which doesn’t mean how well he or she looks on stage with the Donald but rather whom the vast number of the 60% like.
By any way you measure it, the anti Trump vote of a Biden Harris ticket would have the best chance of winning — period.