Are you weighing your food? Reading that you’re eating 3500 calories and losing 1-2lbs a week, but you gain fat easily, seems contradictory. You do burn some more calories digesting protein vs carbs or fat I believe, however I don’t think that would account for your weight loss. Are you weighing all of your food, and most definitely getting those calories and macros?
Are you trying to gain weight? Assuming so based on your post. You could lower your protein to 220, and raise your carbs and/or fats. If your total calories truly stay the same, and your macros shift, as long as you’re not eating processed sugary crap, you shouldn’t be gaining weight due to higher carbs. Especially if you’re eating protein and fat with your meals, your blood sugar should be stable. If you’re happy with your carbs where they are, you could keep your carbs at 325 and raise fats to meet your total caloric numbers.
I’m a huge advocate for having a food scale and weighing everything when you’re getting this specific about total cals and macros.
What are your typical protein, fat, and carb sources?