The Blume type soft close devices whether separate or integrated, require some spring closing force during the last 3-4" of door closing travel. There are some Butt hinges that have springs, but many do not. If you can find some with springs that suit your tates, Blume makes the soft close devices that can be easily added to almost any cabinet. Door latch magnets typicaly will exert a barely noticeable force at about 1/8" distance. Not enough force and not enough distance to operate a soft close mechanism. I used a recessed magnet catch in a set of double doors. Two 1" dia X 1" long neodymium magnets set into the frame from the top. and two !/2" x 1" long neodymium magnets set into the top of doors. Nothing is visible. They work great as a latch. They will pull the doors closed from about 1". They do not act as a soft close. as the door swings shut when it gets in range of the magnets the magnetic pull accelerates the door and causes it to slam harder. If I open the door slowly the magnetic pull is noticeable, but if i just yank on the door like I normaly do, it's not noticeable. After closing, the doors are held about 1/8" away from the door stop molding. I wish I had tried this sooner. I would have used this type of latch on several closet doors and the pantry door. But not on the cabinets. I would compromise on almost anything else if I had to to get the Blume soft close on my cabinets.

The longest I have - which is 24". I have 2 of those that length. I will say that prior to the countertops being installed, we used the contractor's long level (a long one that spanned several cabinets) - and we checked out the leveling of the base cabinets. They were spot on, side to side, front to back, wherever we laid the level. I will say that is the one thing he seemed to do well. I was thinking about contacting Kraftmaid, as we had this issue with the pull out trash. A Kraftmaid rep happened to be at our house for something else - and the rep fixed the pull out trash as we told him our contractor said he had done everything he could to get it level (one side was not level). The rep fixed it. I don't know exactly what he did to fix it though, I was speaking with the other person there with him about the issue they were there about.

"A flush install with full overlay cabinets would be weirdly recessed since it’s even with the faceframe and not the doors." My Ikea cabinet doors (for example) are 3/4" thick. The Sharp microwave door is about 1-1/4" thick. I don't see why 1/2" of material couldn't be cut from the top and upper portion of the side, front edges of the cabinet to accommodate the recessed "spaceframe". The oven would the be pushed into and attached to the spaceframe. The installed oven front would then be flush with the surrounding 3/4"-thick cabinet doors and drawers.

^5 Sammy. Between this forum and YouTube anything is possible. This is timely because the cabinet door has been sitting there for a while - my lack of desire of motivation - and we might be moving sooner, like 60-days sooner. Now what do you know about grading and decomposed granite on a side yard? kidding. that's a whole other post!