Issues with the mobile view of images and grids

Hi,

this is my site https://einfachmutter.de
And after the hero image I try to add a grid of 5 images.
On laptop it looks fine, but the first 4 have one size and the 5.image is smaler.
And on mobile view the first images arent responsive, only the last image is shwowing up the right way on mobile. The others ones are somehow to much in right position (cannot explain it better, please take a look on mobile). Maybe this is because the first 4 image dosnt have the same size like the 5. image.

And I have the same issue with the different size of last image when I use normal image mdeia element in grid.
I tried the same the folowing way: I added a grid, but as opposed to adding the images as backround I added a media image element into the grid. But now matter which distance I choose, the images always are too much to the right size on mobile view (I choosed middle position). And when I make the distance to 0, then its like the issue with the grid. And like above, the last image alsways have a different size then the 4 images before.

Can you please help me with this?