Of all the positions where defense is a major concern, I see Devers and Dalbec as the best chances for improving at their positions.
Devers has done very well, defensively for very long periods of times, but then seems to slump on defense, many times while also struggling at the plate. I'm not sure if he is distracted- lack of focus or just cannot control his arm- ever.
Since Devers and Dalbec have longer team control than Bogey and Vaz, I think the focus for this winter should be SS and Catcher and maybe RF. With Kike having just one year left, and Duran not being a defensive whiz, OF may be a higher priority than 1B and 3B, to me. (Plus, Casas offers a third option before too long.)
I think the best thing to do is stick with Devers at 3B and Dalbec at 1B for another year. We'll know more about Casas. We need to get Devers to buy into working hard on improving his focus, footwork and throwing. Dalbec, too, but he seems to be improving over the last 4-6 weeks, on D.
I'm not a Bogey hater, despite my obsession for great SS D, but I think we need to think about a change, there.