Hi!, I’ve found this hack, with this you don’t need to use any plug-in!
https://adis.ca/post/wordpress-gallery-shortcode-and-lightbox/
the code is a little bit confusing, what you need is to add the lines with the “+”.
What i’ve done is search in my code editor the lines that don’t have the “+”, and when i find it, added the lines.
With that, you should add to the “[gallery]” shortcode the code rel=”lightbox-thenameyouwant” and link=”file”.
hope it’s result usefoult to you.
sorry for my english ??