From southern Ontario Canada with the most climate fluctuations you can imagine. Also a professional cabinet installer. I can tell you almost certainly that a floating floor will not buckle with the cabinets on top. I have never seen it happen personally. I always ask people who claim this to tell me what they think weighs more - the lower cabinets screwed to the wall, or the full depth 36” French door fridge loaded full of groceries that they are going to set right on top of the floor. Same with the stove, and your big ass leather sectional couch. If the cabinets are going to “pin” the floor and cause it to buckle, then all those things are absolutely going to as well. Except that they don’t.