I abide by what a lot of pros do: go hard on hard days, go easy on easy days. Sometimes I mess up and I regret.
I would rather go harder on hard days, more VO2, harder VO2, add 1/2% intensity. But not zone 2 (unless you train purely for endurance and you want to ride more with cooked legs).
Rather, I would do more zone 2 on sweet spot or recovery days (e.g., tuesday in MV plans). But REALLY zone 2, not tempo or sweet spot.