I used to raise ring neck turtledove and they wouldn’t eat anything but cracked dried corn (scratch feed) and laying mash. Which we are able to buy at the local supermarket.
In the wild, our mourning dove don’t eat anything but seed
(maybe an occasional bug) but they hang around fescue pastures and weedy side of the road places.
If you can pick some dried corn out of a wild bird seed mix and crack it into smaller pieces that may work better than veggies.
Also chipping dry dog or cat food into small crumbs.
Don’t force feed.
Do you have neighbors that raise these birds maybe?
The mourning dove that come to our feeders love the finch food which is mostly thistle seed and millet. They prefer the millet over the thistle seed.
My son brought home suet, but a bird rescue website said suet is okay. He’s eating it, and the fruit-carrot-lettuce mixture.