Looking for assembly tips for Ikea Metod base cabinets

That should still be possible. However, if the tile backsplash ends and the gap to the countertop becomes larger, the wall connection strip may no longer be installable.

Hmm, the fixing strip of the base cabinets isn't positioned all the way at the back either, is it, or how is that supposed to work?

Because I have to achieve at least 8 mm to compensate for the 590 mm carcass plus 18 mm front with the 600 mm panel...

Edit: Just noticed that the solid wood panels from Ikea are attached to the carcass with hinges like that, that could also work for me. What distance can I bridge with the Fixa strip? And how is it mounted? Couldn't find any installation instructions for it on the homepage.

The first question is whether a wall connection strip like

FIXA
Wall end strip, gray

is even an option for me. Many people don't like it, although it makes sense.

I have already included the wall trim in my planning, and I would also use it for the IKEA countertop

With the FIXA strip you could bridge a maximum of 2.5 cm. It is mounted like this: It consists of two parts, the lower part is screwed onto the board with the included screws, the upper part is pressed on. If you now let the board stand 1 or 1.5 cm away from the wall, the screws would hang exactly in the slot and you would not be able to mount the lower part. That’s why I would put a wooden slat in the slot, which would be screwed to the base cabinets. So if the slat had the thickness of the slot and the thickness of the board, that would work...

So I would basically have to extend the board by about 10-15 mm with a slat or something similar, which would then be covered by the wall finishing strip...

That's too complicated for me. I will then take a 246x60 cm IKEA board and hope that the 6 cm on the edge provide enough stability for the built-in hob. (I have 4x60 base cabinet elements, but the built-in hob inevitably has to be placed on the outside...)