Have a look at this editor.
On the index page at the bottom is a basic version of the responsive repeating group I showed in the video.
If you don’t want a fully responsive RG then the issue you have with the extra space, maybe related to how the elements are grouped to gether.
When I make RGs to display products, I create a reusable element that is the ‘card’ to display all details of the ‘listing’. After that I drop it into an RG and I usually don’t have any issues.