As @Sangeetanahar pointed out, there is too much “air” in your images.
Ideally, you should crop them tighter and re-upload.
Or, use an app to crop them in place, like Hextom: Bulk Image Edit & SEO which can do it in bulk.
However, it this is really not an option, you can add this code to either Theme Settings=> Custom CSS, or Custom CSS setting of relevant section(s):
.product-item__image > img.image__img {
width: 150%;
max-width: 150%;
transform: translateX(-16.66%);
aspect-ratio: 1;
}
This will make your product grid images 1.5 larger.
Not really recommended though. Only as temporary measure.
Screenshots before/after
