What works well for my dragon:
* Greens as whole plants. I do this e.g. for golliwog (callisia repens) and herbs. I currently try growing kale, which normally should work but is a challenge in our climate zone.
* If greens can't be bought as whole plants and can't be grown: I bundle them as a bouquet and put them in a shallow dish with water.
I'm not chopping up greens anymore. My dragon also clearly prefers what is a whole leafy plant, or at least looks like one (bouquet).
For other vegetables like squash I chop them, put them in in the morning, and what is left over is then for the roaches and worms.
I see you write
From this I assume you don't eat much vegetables yourself? (I simply mean this as a statement, not a criticism.)
Why I'm asking: We eat a lot of vegetables, so we never buy something only for the dragon. So for example with the squash, a bit is for the dragon, and most is for us, so it's gone within 1 - 2 meals depending on the size of the squash. Same is with other veggies like bell pepper: we had a dish yesterday that contains bell peppers, and a few raw slices of that peppers were for the dragon. Also kale and other greens: One leaf for the dragon, the rest for us.
If you don't like to eat those veggies for your meals, and don't like to incorporate them into your diet, it might be an option to freeze them already chopped. And then give them to your dragon thawed. Also, unchopped veggies last longer in the fridge, when you just cut off slices.