Welcome Lau and Lolo (you could call him Lolo instead of Lola -LOL).
Gloop and seeds (I use 50% cockatiel mix which has a bit of striped sunflowers in it and 50% a small pisttacine mix that is safflower based) is not enough, you need to provide raw produce on a daily basis (one fruit, one veggie, one leafy green or cruciform - a different one every day) to provide a rounded up nutrition as well as entertainment and variety to keep their interest in the food.
He might be getting a bit lonely out there... are you a stay at home person or do you work outside the house? Because if you are home all day long, he would love coming in a spending all day long with you. People talk about their been entertained by watching the birds outside and I agree that having birds around is better than nothing but those birds are not his flock and he needs company that he knows and is close by so maybe you could consider doing this for him.
I also strongly recommend you take him to the vet and get blood work done, including a bile acids test because, after all those years of pellets, seeds and nuts, he might have the beginnings of fatty liver disease and this is perfectly treatable and even curable as long as it's caught early enough.
But, Wolf, my friend, you are getting confused, it's not betacarotene into vit A that requires UVB, it's cholesterol into cholecalciferol (vit D3 necessary for calcium absorption).





