Campaigning is a full time job and so is the presidency. Someone could easily have stamina for one but not both.
Biden probably would do better without travel and jet lag.
I would rather have Biden’s handlers continue the job they do than see the historic first woman president Kamala Harris take over.
Since the democrats/leftists seem to think that men and women are the same, and interchangeable, and entirely determined by the subjective opinion of each individual, then whether the president is male or female should be of no consequence, and they should neither make a point of it, nor celebrate it.
But democrats/leftists are liars and hypocrites, so of course, they will never stop talking about "the first woman president".