Firstly remember that the zones are more like vague ranges rather than strictly defined levels where you switch over into different energy systems at a certain wattage.
There was a good episode of FastTalk about this fairly recently and the guy was saying that once you are in a particular zone and training an energy system then there is little to be gained (at least in terms of training the specifics of that energy system) from riding at the top of it vs. at the lower end of it. It’s just more fatigue.
For zone 2 think long and easy. Very long and pretty easy indeed: more than a recovery ride or like you’re riding with your 7 year old kids, but not enough to feel like it’s any real effort. Keep well away from tempo. Save that for a tempo ride, not this one.