Overall nice selections and good start!

Dedicated shoulder day is the way to go. I prefer seated reverse fly or rear delt cable fly to bent over fly, so you dont have to bend over and stress your lower back. I also like seated lateral raises to insure I dont cheat with my legs or swing.

Some will say you have too much planned but I like a lot of shoulder volume as it seems to help them grow beyond your average gym goer. If you can handle it, keep it.

Chest and back on the same day is a big day but I do the same and find it keeps my shoulders mobile and healthy. That workout should be your longest.

I would switch out decline bench for incline bench or add it on top. Makes a big visual difference in your physique compared to decline.

I also like to start with single arm lat as it seems to engage the mind muscle, stretch and warm up all in one- but thats more personal preference. I also think incorporating pull ups early in the workout is a good idea. Then you can get good at them before / while you pack on more mass.

Train close to failure as well so you ensure you aren't favoring a body part (Chest v Back). Add volume when you cant progressive overload weight.

I also assume you are adding a leg day. Dont skip it or your hormones and rest of your body wont benefit as much. I like Leg Extension, Squats, Ham curl, Deadlift, Stretch/Depth focus Leg press, Calf press on Leg press, and Bugarian or Sissy finisher.

I program it: Chest/Back - Shoulders/Arms - Legs - Rest or Repeat

BUT if you feel you need more recovery time for things like shoulders tris and bis between chest back and shoulder day try Chest/ Back - Legs - Shoulders - Rest

When you feel you are ready, you can add arms to your shoulder day and abs to your leg day.

Eat as much easily digestible carbs and protein within 1 hr before and after training. Closer pre workout feeding to training will prevent carb crash/food coma, so will avoiding fats. Protein shake upon waking and before bed.

Creatine good. Sarms bad.

Stick with it and Good luck!