My beardie is about 8-9 months old and won't eat greens at all no matter what I do to them. I've tried putting insects on them, using this bearded dragon salad dressing stuff. Nothing works. She sometimes eat a few but barely. She eats insects fine but does not even seem interested in greens ever.
At that age she just needs more protein so has more interest in bugs. That's pretty normal. Just keep offering salad so it's familiar. You can put the leftovers in the bug bin for them to eat. Roaches are especially good at taking care of leftover salads. I wouldn't bother with the salad dressing. It won't add any benefit and isn't likely to be very healthy for them. When she gets between about 12-18 months and her growth slows, offer bugs less frequently and try to work her onto more salads gradually. For now just continue giving her bugs and making salad available if she wants it.