The machine overhead press is a great shoulder exercise that allows you to focus on shoulder activation without having to control the weight like you do on the dumbbell and barbell overhead press.
I recommend that you try some machine overhead press sets in the 6-12 rep range going nice and heavy, as well as trying some sets where you aim for 15-20 reps or 45 seconds time under tension to trigger the metabolic stress phase of muscle growth.
The machine shoulder press exercise will be a bit dependent on what equipment you have available in your gym.
However, if you can get into a seated delt machine and focus on placing the palms in on the handlebars, you’ll find you get a really good burn in the front and lateral delts.
Single Arm Decline Crunch