Have you ever tried 5/5ing the stamina talent on combat veteran? Because that's all you need to do!
Not really, if you have a lot of stamina using abilities, you can burn through stamina a lot faster than the ~3 a turn that gives you (depending on your mastery multiplier for it).
You will definitely burn through the stamina, but it goes a very long way to keeping you in the fight. It's more related to management and the kind of fight you're having, expecting full resources at all times isn't realistic tbh.
I'm just saying most people who have stamina issues don't know how good that talent is, or they burst trash mobs with all their talents, possibly both.