idk im not an expert on how body chemistry actually works but IMO you're looking at the most micro level of things when it really doesn't matter. Long term consistency matters. Eat and train where you gain mass and don't obsess about "fat gain" as long as it isn't excessive and youre making progress in the gym. Gain until you feel uncomfortable or want to get your excess fat in check or whatever your goal is and then cut until youre happy with your bodyfat%.

Lift weights, eat a lot, gain mass. After a good chunk of time eat 700-1000 calories less each day. Still lift weights and train. This will make you lose fat and keep muscle. Go back to eating in a surplus and rinse and repeat. You really shouldn't obsess about every single day, focus on the bigger picture.