If you do not want fat loss and your goal is purely to gain lean muscle, I would eat slightly above your maintenance levels on workout days and
at your maintenance level on rest days
Instead, I'd set my
calories at maintenance levels and focus on strength training, and let your body composition make a favorable change (lose body fat and gain muscle) at your current weight.
I have no problem with someone staying
at maintenance levels while lean bulking on off days but by doing so you're being too risky and have a higher chance of being in a deficit than anything else.
I'm sure it is paying off:) I would suggest
eating at maintenance level or slightly above (in a surplus) if your aim is to gain muscle.
When you reach the point where you lost as much of the fat as you wanted to lose, increase your calorie intake (by adding back some carbs) so that you are no longer in a caloric deficit and are
instead at your maintenance level.
When consuming calories above or
at maintenance levels you should strive to get the majority of your calories from carbohydrates.
Try implementing a high calorie day or two each week where you eat
at maintenance levels or slightly above.
At that point, just maintain your lifts in the gym, and eat
at maintenance level.
Because you're eating
at your maintenance level, you're not going to gain body fat during this time.
No it wouldn't stunt growth if you are
at maintenance levels, it will only stunt growth if you are in a deficit.
If they are not trying to lose any weight, then they should eat
at maintenance level.