"I was told by my breeder that (1) the pellet diet was well balanced and feeding fresh or other supplementation would not be necessary. I have tried feeding fresh fruits and veggies but she won't touch them. I think I may try putting some veggies in a food processor and mixing that in with some seed hoping she'll accidentally eat the greens. (2) She has a mineral block which I have never seen her touch. (3) To be honest, making fresh chop every day for one budgie is a little higher maintenance than I'd prefer. I want her to stay on pellet so what else can I feed that won't make her turn up her nose to the pellet? I'm almost afraid to try new things because she is already picky and I don't want to spoil her on a food she can pick the good stuff out of.
She has paper toys, plastic, wooden, bells, fabric, string, and rubber toys. I have tried foraging toys with no success; (4)I guess because she doesn't know there is millet in them. I will step up my game on enrichment toys though.
As far a cage mate, I have been considering it. However, I brought her into my home to be a companion animal hoping to keep her happy and enriched without other birds. (5) I really want to try and be her flock. If it can't be done and she needs a bird companion to be content then she'll get a sister."
(1) The pellet diet you have her on is balanced, and - nutritionally - she wouldn't need anything else. But from another standpoint, pellets can be horribly boring and offering fresh fruits and veggies is good stimulation and "spices" up their diet. So I'd offer fruits and veggies, just less often!
(2) In my personal experience, budgies only use mineral blocks and cuttlebones when they need the extra vitamins/minerals. You might never catch her using it, but she uses it as needed which is awesome!
(3) Since you're feeding a pellet-based diet, you can probably get away with only preparing fruits/veggies 4-5 days a week and be okay. But because you brought a bird into your home, you signed up for having a "high maintenance" pet. Budgies aren't low maintenance just because they're small. They require work, time, and dedication just like every other parrot.
(4) I got past this by playing with the foraging toys until some millet falls out so she understands the concepts, and letting them watch me put millet into the toy!
(5) To ease your stress, even if you get another bird as long as you spend lots of quality time with both of them every day, you can still be their flock! It would just be better for her to have a friend of her own species around while you're away so that she doesn't get bored or lonely and develop bad behaviors.