Mount bathroom furniture on walls tiled halfway up

Hello,

we have purchased bathroom furniture from Puris and would like to install the wall cabinets. Since our walls are only tiled up to 1.20m high, there would be an air gap above the tiles.

I am now considering how to best do this. One idea would be to shorten the side panel a little. But with which tool, so that the wood does not look frayed afterwards?
Or do you have better ideas?

One idea would be to shorten the side panel a bit.

What does the side panel have to do with the height of the tiles?
I would have suggested simply hanging the cabinet lower so that the "air gap" disappears or to accept the "gap" as normal. However, it could of course be that I misunderstand the question and the situation.
Why don't you give us a photo :)

Exactly what is the background of the question? Is it an aesthetic issue, meaning that you don't like the gap visually? Then seal it with acrylic (paintable) or silicone (not paintable, but more elastic). Up to 5mm, this is probably easy to do, beyond that I would insert a backing rod so that you don't need too much sealant. I wouldn't notch out all the side walls.

I plastered the wall to the level of the tiles. That's how you do it. You can also cut out the furniture. DIY can be done with a fine saw blade.

We will have the same situation in our guest bathroom as well. I only noticed it this week, after the bathroom was fully tiled. The cabinet is not hung yet, but it already annoys me because in the untiled upper area there remains a (Staub) gap. I was considering whether to insert a plasterboard cut to fit and then apply acrylic around it.

Have I understood the problem correctly?