Reformer pilates is strength-based and gives you a full body resistance workout with plenty of variety. I love it. Not competitive at all, very beginner friendly.

Yoga is more mind and body together. I do Yin yoga, which barely qualifies as exercise. You lie in one pose for a few minutes at a time and get into deep tissue or fascia or something- you feel all tingly afterwards, and nice and relaxed.

Vinyasa yoga is far more active and has lots of movement and active poses flowing into each other- it builds flexibility and some strength.

Other yoga forms are somewhere in between- hatha, slow flow, etc. All are accessible for a beginner, and not at all competitive.