Good evening,
Thank you for the further answers.
The carpenter has already advised us over the phone against the solid wood panel on this side of the kitchen unit. In the long run, it will inevitably lead to problems... Yesterday, we bought a laminate countertop as a temporary solution and are calmly considering what to do there in the long term.
The carpenter is still coming next week because he has to cut it, as the wall is quite crooked and uneven (very old house after all...).
Wishing you a nice weekend
Taunuskind