More photos

Were you planning on any type of crown? I don’t think the 1/4” difference will be noticeable... I would bet most kitchens have variances like that.

How much distance do you have between counter top and backsplash? Can you lower the cabinets at all to make it less obvious? Were you planning to finish them with trim at the top? If you had a bigger gap you could just cover it with trim.

You can get very narrow trim at HD or Lowes - it comes in various widths. You can paint it to match your doors: https://www.homedepot.com/p/Woodgrain-Millwork-WM-254-1-2-in-x-3-4-in-x-96-in-Wood-Pine-S4S-Moulding-109613/203898784?MERCH=REC--pipsem--NA--203898784--N

@ Kaylie... We've got just over 19" between cabinet bottoms and what will be the finished counter. We wanted a bit more than we used to have 16" because the IKEA uppers are deeper. Plus, we will be doing some sort of under cabinet lights (likely from IKEA as well, just not sure which model).

One thought was to make the doors taller than the cabinet and leave about 1/8" gap at the top. The finished ends would either run up tight to the ceiling, or to the same height as the doors. Obviously this option would be no trim at top.

Other option would be to just plane down some material to the exact thickness of the gap and keep the edges square, but bring it flush with finished end and cabinet door. So when the cabinet door is closed the edges of the finished end and the top piece would all be flush.

@ Hillside... We were going to do crown, however as you know IKEA only comes in 30 and 40" tall uppers. We had 36 before and knew we didn't want to get smaller so we went up to 40 knowing the crown idea would likely be tossed....and I had zero interest in shortening the uppers.

The problem is that 1/4” with only an inch total is more likely to be noticeable, where 3/4” in a 5” crown isn’t as obvious.

If it was my kitchen, I’d probably drop them down an inch so I had a little more room to work with. (18” is standard, so it’s still more than the 16” you had before.) My husband absolutely LOVES to redo things after we’ve done them, so a secondary option for me would be to use a small, thin piece of wood attached to the front... I would probably go slightly deeper than the doors (1/4”?), so that it casts a nice shadow line, and it gives the benefit of being more forgiving than trying to match your door depth precisely, which can vary, especially once you start adjusting the hinges after install.

A professional installer would scribe a flat trim piece to the ceiling to create a level surface to butt the cabinets against. Is that a fix that you could attempt? It’s easier than it sounds as you have a slope rather than waves. Look at a few YouTube videos.

Drew this up quick.

Current configuration showing gap on top and gap at back wall due to bracket system.

This shows a flat finished end panel with a flat piece on top brought flush to the cabinet door and finished end.

Same idea as above, but with an end that matches the door. This looks a little goofy if i run the panel all the way to the ceiling and maintain the same rail/stile widths because the top rail of the finished end is no longer in line with the door.

Close up view of the options above.

I like a finished side panel, personally. I think it helps to keep it from looking like a basic IKEA kitchen.

I would run the flat piece on top over the side, as well, so everything lines up.

@ Hillside... I thought about doing that but i was just trying to avoid having another seam above the finished end panel.

I was thinking something like this:

Or this, but with just the bottom portion:

Scribe a trim to the ceiling.

Both options below have the top piece extending past the face of the door and finished end by 1/4"

Squared idea like Hillside suggested:

Same as above but with a slight chamfer to break the edge:

Either will be fine as a trim. But unless you scribe to the ceiling, the uneven gap will remain. Just adding trim won’t fix the issue. You can use shorter cabinets, to move the cabinet top significantly away from the ceiling if you don’t want to scribe.

@ Cooks.. Understood. We have textured ceilings so i won't be able to get a tight fit anyways. I would have to either scrape the texture off where that piece would make contact, or just get it as tight as possible and then run a bead of caulk.