Personally, Tai Chi Chuan, which is weak in fitness, is not suitable for competition routines, because competition routines are designed for competitions, so the design of movements will be more difficult and the effect on fitness will be worse. I suggest that you'd better practice traditional routines, because generally speaking, traditional routines are relatively long, and the same action is often repeated several times. If you can't stand the whole set of movements, you can only practice a few movements, or connect several movements in series, because only the traditional Tai Ji Chuan routine can reflect the real charm of Tai Ji Chuan.
At present, there are five schools in Tai Ji Chuan, namely, Yang Chen, Wu Dance and Sun Wu. If the body is weak, it should be Yang Wu style.