Can’t seem to gain any muscle mass. Type 1 Diabetic

Like most things things are individual and vary from person to person, I. Quite lucky and put on muscle relatively quickly. But from what I’ve read and from personal experience it’s a lot to with protein ,as they are the muscle builders, ( amino acids etc help too ) so plenty of chicken oily fish etc , plus when your pushing weights make sure you take time off from different muscle groups , the muscles basically break down when weight training and then rebuild bigger ! So if you continue pumping iron without rest periods it can have an adverse effect, a lot of people I know tend to do legs one day , arms the next ,stomach the next etc etc . sorry if I am trying to teach grandma to suck eggs
Good luck and keep on pumping

I was in a similar situation and talked to the doctor found I was producing almost no testosterone

Was put on trt and have gained muscle since.. but also a lot more energetic since

However that may not be the case for you.. not every one can grow muscle

Also 3000 calories wouldn’t be the only requirement it would need to be a good mixed diet with plenty of protein.. along with enough sleep. And an exercise regimen that exercises all muscles across different days so that muscles get reset as they only grow on recovery days