It depends on how fatiguing Zone 2 is which depends on how narrow Zone 3 is.
In general, the closer you can train to the top of Zone 2 (your aerobic threshold), the better.
BUT as you get fitter, Zone 2 intensity will become more and more fatiguing, so you’ll need to replace it with more of Zone 1 or even easier.
How did you test your thresholds? What heart rate is the top of Zone 2? And what HR is the bottom of Zone 3?