If you goal is to gain muscle and your diet plan puts you in an 800 kcal/day deficit, then your diet plan is wrong.
I don't know how you came up with this plan, but when planning a diet one would normally pick a daily calorie target first, then determine a minimum daily protein intake (usually 1.5-2g per kg of bodyweight for non-obese strength trainees), then distribute the remaining calories among fat and carbs.
So let's initially assume that your calculated 3000kcal TDEE is accurate. If you're merely "going to the gym", then maybe a 200 kcal/day surplus is appropriate. Or if you're starting an honest strength training program (i.e. squats, deadlifts and presses are the main exercises in your program, and you're increasing the weight on them every workout) then 500+ kcal/day would be beneficial. We'll start with 3200 a kcal/day target.
At 80kg bodyweight, if you want to eat 2g/kg/day protein, then that's 160g, which contains 640 kcal, since 1g of protein contains 4 kcal. That leaves 2560 kcal to distribute among fat and carbs as you desire. It really doesn't matter what ratio you eat fat and carbs in, so you could easily just stop here and make your daily plan "3200 kcal, including at least 160g of protein". But if you want to divide the fat and carbs, say, 50/50 by energy content, that would be 1280 kcal of each. Since the energy density of carbs is 4 kcal/g and fat is 9 kcal/g, your carb and fat intakes would come out to be 320g and 142g respectively.
Next you need to determine whether your calculated 3000kcal TDEE is actually accurate. The way to do this would be to try it for a couple of weeks and weigh yourself regularly, observing how your bodyweight changes. A 500 kcal/day surplus is usually thought to add about a pound (454g) of bodyweight per week. So if you think you're on a 200 kcal surplus and you gain 1kg in a week, then your TDEE is actually much lower than you thought, and you need to recalculate your diet plan with a lower target energy intake. Or if you lose weight or fail to gain weight, then you would need to increase your energy intake. If you gain weight but it appears to be fat rather than muscle, or if you're still gaining weight but your lifts aren't increasing in the gym, then that implies that you aren't doing enough volume in the gym, and you need to be doing longer or more frequent workouts.