grid layout doesn't crop

Absolutely!

This might help out (if you did not see this tutorial)
Create an Image Post Front Page like the demo

Completed the tutorial, but still have some odd white spaces.

When you uploaded your photos, were they at least 570×570 or larger? If they are smaller, it won’t work because the thumbnail generator for this layout does not “upsize” the images if they are smaller. Also, you will want to make sure that the customizer setting to create the thumbnails is enabled before uploading, otherwise you will need to regenerate your site’s thumbnails with a plugin, such as this example

…but the important factor is to make sure your images are large enough to create the required size of 570×570

Perfect! The images were cropped exactly with the Thumbnail Re-generator.

Problem solved. (THANK YOU)

Great to hear ??

It is troublesome.
It should be the default.
Need wasted time of life?
It is contrary to the spirit of the word press.