the weight dropping from 60 to 50kg on bench is almost certainly a recovery and volume issue rather than a technique one. the three exercises you're doing are solid choices but here's what's probably going wrong you're likely not eating enough protein or overall calories to actually build muscle, because if you're trying to get lean at the same time your body is basically fighting itself, you can't efficiently build and cut simultaneously especially as a beginner. so dial in nutrition first, get at least 0.8g of protein per pound of bodyweight daily, that's non negotiable. second thing is progressive overload, you need to be tracking your weights and reps every single session and actively trying to beat your previous numbers, even by one rep, because without that your chest has no reason to grow. third is make sure your bench form is actually loading the chest properly a lot of people are accidentally making it a shoulder and tricep dominant movement, so focus on retracting your shoulder blades, keeping your chest up and really squeezing the chest at the top of every rep. also add cable flyes or dumbbell flyes instead of just the machine butterfly since it gives a better stretch under load which is really important for chest growth. and finally make sure you're resting enough between sessions, chest needs at least 48 hours. fix the nutrition first though, that's almost definitely the main issue (atleast most common prob)
