I love simple solutions. Here’s a very simple layout technique with core WordPress blocks: A horizontal row of four boxes on a big screen that becomes two rows of two boxes on a small screen. It’s best with an even number of boxes but probably works with odd numbers. I haven’t tested an odd number.
It’s very simple, but it’s a very useful option to have in your library of layout techniques.
The row has four boxes on big screens.

On small screens, this layout becomes two rows of two-boxes.

Block Nesting
In the block editor, nest Row blocks and Group blocks like this:
Row (container row)
Row (inner row)
Group
Group
Row (inner row)
Group
Group
The Group blocks contain your content. The boxes of content should have similar dimensions, but it probably works with some differences. Experiment a little to see if it works for your content. In the example above, they each contain a headline and an image. The headlines and images link to other pages.
Row Settings
For the container Row block, set Allow to wrap to multiple lines to ON.
For the inner Row blocks, set Allow to wrap to multiple lines to OFF.
To change this setting:
- Select the Row block in the Document Overview (the list of blocks on the left).
- Toggle the Document Overview section on and off with Shift-Alt-O
- Find the setting in the Layout section in the Settings section on the right.
- Toggle the Settings section on and off with Crtl-Shift-,
- Toggle the Allow to wrap to multiple lines setting.

Conclusion
That’s how simple it is. It’s a very easy layout technique that’s very useful when the content has an even number of boxes.