Hello, Arms,
Thank you for the response.
1/ This is independent of our theme.
Is there a reason you are using large png images, but not jpg? Try to use https://png2jpg.com/ and then compare the file size of the images.
2/ Please edit any page using Elementor page builder > go to Site settings > Lightbox > Image Lightbox > disable.
Let us know the result.
Kind Regards,
8theme team