SpaceX mocked up a plan to reuse the second stage of Falcon 9. https://www.youtube.com/watch?v=sSF81yjVbJE These plans were scrapped to concentrate on Starship.
If the Falcon 9 is big enough to have enough margin to support second stage reuse, New Glenn definitely does too.
However, I suspect 2nd stage/full re-use is fundamentally so much harder than 'just' 1st stage re-use that it requires a full re-use design from top to bottom, a la Starship/Superheavy.
Of course, Blue has been historically far more closed than SpaceX, so it's possible that they have legit, in progress full re-use! That would be great.
The push to scale up and become an operational launch company has only ramped up in the past several years.
They still move somewhat slowly and are fiercely private, but those early years were targeting different goals.
I could be wrong, but I don't think Blue has any plans (at least in public) for full re-usability.
Though New Glenn is a beast, it's not that much more powerful than Falcon Heavy, and both of those platforms still throw away the 2nd stage.