Absolutely, we have to win. A second 4 years of this administration or anything remotely like it would most certainly spell the end the America we once knew. But more than winning, we also need someone who is a fighter as you said. Someone who can suffer the slings and arrows of both a rigged, partisan system and mass media which demonstrably aligns with one side as well as your own party -- where you hope at best won't try to undermine you but can't be relied upon for support either.

Then, as TIOK pointed out, control (or at least leverage) over the Congress is also necessary. Otherwise you end up in stalemate and incapable of undoing the damage of the past 20 months. Executive orders only go so far. Though the first order of business for the next Republican President should be a single sweeping E.O. wiping out every single one issued by Joe "what am I signing?" Biden.