Hello @deranaloge,
Thanks for writing to us.
No, it is not possible to add the Gutenberg gallery inside the layout builder and regretfully there is no element of gallery at the moment.
You can use the default WordPress Gallery. For the gallery, I have created a default WordPress gallery. To create a gallery you need to click on the Add Media button —>Create gallery
Now you need to set the image number per column and image size. Please note you need to set the “Link To” as “File”.
It would add a shortcode to your content for the gallery.
For example
[gallery columns="4" link="file" ids="2029,2028,2027,2018,2017,2016,2015,2014"]
After adding the gallery you need to add this shortcode to make the image open in a lightbox on click event.
[lightbox selector=".gallery a"]
You can add this shortcode to your layout with the help of the Raw content element or Text element.
Hope it helps
Thanks