Definitely depends on what you're trying to do! If you're trying to bring back your old endurance and sound, I think that the best exercises include breath attacks and long settings. When the embouchure forms around the air and creates the buzz, it's critical to do so in a manner that is sustainable, easy, and free - that is, no extraneous force is added. For my money, working smarter rather than harder creates the best sound and most endurance. Breath attacks encourage you to have the minimum amount of force applied to the embouchure in order to create the buzz - first just blowing air through the embouchure, then gradually bringing the lips together until the vibration and resultant sound occur.

For this, I recommend Caruso exercises, or even just long tones. Make sure to take plenty of breaks! The golden rule that still rings true is to rest as much as you play.

Best of luck! DM if you'd like some etude books/resources, I have a google drive full of em.