I think that this would look much better if there were smooth transitions when scrolling instead of it snapping to the next zoom position when you scroll.

I agree with this :D just downloaded the mod and really would love this as I am so confused when it comes to minecraft modding.

Added in Just Zoom v1.0.2!

How do I enable this? I can't find an option for it in the config.

It's lerp_amount and is enabled by default.
Keep in mind you need to be on v1.0.2.

oh, it's not a thing on 1.19.2, that's why.