I have been pleased with 2.5 reeds. I am an old geezer, and have found, until recently, that they were best for what I play. I have recently begun using fibracells, as well, and I think I actually rather prefer 3 reeds, now. When I took clarinet back up 7 years back, I started with a 2 Reed, and that was best for me at the time. Experiment. We are all different. I cannot use any Reed beyond a 3, or I get exhausted, as well. One's Reed and mouthpiece (assuming the clarinet seals well, and is adjusted correctly, of course) are by far the most important mechanical components of a horn, for playing satisfaction. Technique is equally important, but that returns in time. Since you were good, you can be again.
Cheers.