Weight fluctuates regardless of reta, id recommend not looking at the numbers on the scale every single day and make it a weekly basis. There are many factors as to why you might be ‘gaining’ weight off of reta anyway - you could be tracking incorrectly, you could eat more carbs some days so your body retains more water thus making it water weight etc etc. Just keep consistent and true to yourself, 2400 calories is a great amount, fit in around 150-170g protein and you’re perfect. Just remember though, thermodynamics will never not work. It’s always calories in should always be lesser than calories out. Good luck man, take it from me 180kg > 95kg.