New floor up to new cabinets already installed or under? New construction home
Your Builder's a knot-hole, he should've figured in the wood floor for you. Don't mess the cabinets nor countertop, it shouldn't be glued to anything, knot-holes. This means no need to do anything with the uppers. But, do put the flooring under removable things, if there's room for it. Like, Refrigerator, Range, &amp; even Dishwasher, easier future servicing. The vent can just slide up with a top cut, glue the cut-out piece to the vent hole's old bottom.

Now then, you might luck out with the toe-kick that's already there, for the new floor &amp; the vent. If the toe-kick is solid &amp; has no seams below each cabinet. Then, it was applied after the cabinets &amp; can be pried off or even un-clipped, trimmed &amp; reinstalled on top of the new floor, trim the top edge. You can also do this with many per cabinet toe-kicks too, if they're topically applied &amp; not Ikea-like cam-lock nor bracket applied. Some Trim Saws could possibly cut the toe-kick that tight to the floor too.