I'm still not sure how much of the "slow play" of prospects is Chevy, and how much is on the coaches. I think it's also a function of where the Jets' management and coaches see the team and its contention window.
Recall that after the 2015 playoffs (Jets swept by Anaheim) the Jets realized that they didn't have enough talent in their core and needed to spend a couple of seasons transitioning to younger and more talented players. Over the next 3 seasons they traded Ladd and transitioned to younger players (Ehlers/Copp, then Morrissey/Hellebuyck, Connor/Laine, etc.). At the time, Chevy and Maurice were clear that they were transitioning to their youth because they realized the core wasn't good enough.
The big question right now is what Chevy and the coaches think about the potential of this roster. Do they think they can take another run in the next couple of seasons with this core, or do they think they need to add some youth and skill to get to the next level? I think they are much more confident in this core / roster than they were after 2015, which might mean that they slow-play Lambert and some of the youth a bit more than they did in the seasons after 2015.
I think this will be a pivotal season. If they have another really strong regular season, then I think they'll try again to make a run (which might mean rentals or "own rentals"). If they look like they aren't really competitive, then I could see them making fundamental changes mid-season or at the TDL to accelerate youth and maybe to change the roster structure (i.e. add a top RD and/or 2C). That might mean trading a core player (Ehlers?) or selling at the TDL (Iafallo, Pionk, Appleton, etc.) to get some draft pick capital for off-season restructuring.