The schedule of my birds varies a lot, there are some general lines but there are loads of variables.
At this moment they get chop on a plate in the morning, sprouts mixed with pellets and Some other things like Anise stars and the like in Some cups and a plate. Then I fill up all their foraging stuff with seeds, add some toys and get everything ready for their day. In the afternoon they often get flowers, the way I give those varies, sometimes in a basket, hanging, on a plate, mixed with other food etc. They get a bit of dried seed mixed with dried berries and the like and the fresh stuff I have available(I freeze my chop) like broccoli or berries, or a bit of fruit. I fill up their foraging activities again or add new ones. A bit later they get more sprouts mixed with pellets.
Mixing pellets with seeds or spouts is a great idea. Softening the pellets with a vit of water could help too. Even more so when you mix the soft pellets with something else, everything Will stick together a bit and he can’t pick put just a seed, there Will be a bit of pellet next to it. Show him things are food by pretending to eat it yourself and be excited a about it. Sometimes it helps to pretend he can absolutely not have it. That might Peek his interest. You can also try SS skewers and skewer veggies on it. My birds enjoy taking Nibbles of veggies on that while they usually only want to eat cut up veggies. Most important it to keep trying. One of my lovebirds and my cockatiel when he was alive were horrible eaters. My cockatiel was rescued and a senior, he didn’t eat any veggie but when you showed him junk food he would come running to take a bite. The first veggies they ever tried were the orange ones, like carrots and pumpkin. Blue(BCC) tried carrot as first veggie too, and so did Fëanor, my other lovie. Even my ducks like carrot! Perhaps Picasso Will like it too
Keep offering it at about the same time, that worked for me. I found offering things from my hand helped too.