Chair listings advertise a dozen adjustments and most of them are noise. Four decide whether you finish the day comfortable.
Seat height comes first, and it is set by your feet, not your desk. Feet flat on the floor, knees level with your hips or a touch below. If your desk is too high after that, raise the keyboard or your monitor rather than the chair, or add a footrest. Dangling feet put your whole body weight through the back of your thighs, which is the single most common cause of the numb, restless legs people describe by mid-afternoon.
Seat depth comes second and is the adjustment most people have never used. You want two or three fingers of clearance between the front edge of the seat and the back of your knees. Too deep and you slide forward to be comfortable, which throws away the lumbar support entirely. Too shallow and your thighs are unsupported. Chairs with a sliding seat pan solve this; chairs without it fit only people of a certain height.
Lumbar support is third. It should press into the small of your back, not your shoulder blades and not your belt line, and it should be firm enough that you notice it when you lean back. Fixed lumbar shapes work fine for people the designer had in mind and poorly for everyone else, which is why height-adjustable lumbar is worth paying for if you are shorter or taller than average.
Armrests are fourth, and they are the one most people set too low. Raise them until your shoulders drop and your forearms rest level with the desk. If your shoulders are creeping up toward your ears while you type, the armrests are the reason, not the keyboard. Armrests that adjust inward and outward matter more for wide or narrow shoulders than any spec on the box.