The opening for the pendant light is an actual junction box with wires etc so don't worry about finding a 3.5" recessed fixture..., that junction box will have to be removed to accommodate a recessed light in that location.

This means you should probably try to get a recessed light housing that matches the other recessed lights in size etc... It also means one of the sides of that junction box is typically attached to a joist (or truss if there's no floor above), the opening will have to move a bit to accommodate a recessed light.

Maybe you can check and see if it's simpler to slide the pendant a bit further away from the upper cabinet and/or convert the single door to a double narrow door version(with glass doors)?

Or take the light out of the equation, depending on how it was wired it will be quick or a bit more involved (if there's more than one pair of wires in the box that splice needs to be relocated somewhere else, or that box needs a blank cover, not pretty in a brand new kitchen).

You'll have to have a conversation with your electrician, and probably your cabinet maker (and your drywall finisher). Try to stall ceiling paint if you're at that stage.