Push
Straight-leg bench dips are the harder chair-dip version. Fully extending the legs makes the arms support a larger share of body weight—an essential bridge between bent-knee dips and parallel-bar dips.
With legs straight and heels on the floor, the center of mass shifts and arm load rises sharply. Many people who hit 20 bent-knee reps only manage 8-10 with straight legs.
Elevate the feet on a second chair at the same height. That approaches parallel-bar dip load. You can also add weight (backpack) on the thighs.
Do not drop past the point where the shoulder feels tense. Deep dips without enough strength can irritate the rotator cuff.
3×15 with straight legs before moving to parallel-bar dips.