He's going to eat what he wants to eat and this is the time of year where some geckos (though not usually juveniles) slow down on eating. One thing to try is to mix it up with some different feeders: super worms, roaches (if they're allowed where you live), silkworms, hornworms. Not waxworms. You don't have to try all these, but some variety may tempt his appetite.
You ask for advice and here's mine, FWIW.
I have a, I'm pretty sure, 8-10 week old Leo. Got it about a month ago.
For the first couple of weeks it was about 4-5 bsfl and about 3-4 small mealworms.
For the last couple of weeks, its been a couple of bsfl, 5 mealworms and 2-4 dubia roaches.
I really wish I could buy 50 bsfl at a time but 100 is the smallest amount I can order. At least they're cheap.
I gut load all my feeders with bug burger and some veggies. Usually cucumber or yellow squash. The bsfl devour it but the meal worms and dubias are not so voracious.
I also dust with Repashy Calci-Plus.
Its been gaining about 3-3.5g per week. Not sure if that's good, bad or ugly. Seems healthy.