Hello,
1) Downgrade WP to version 5.7.2. Theme does not support WP 5.8 at this moment. We are working on new theme update that will support WP 5.8.
2) Ok. I passed the issue to our developers. I’ll inform you once they fix the issue.
Anyway, images that you use on your site (not just for this product) are still very big and the page is too heavy https://prnt.sc/1ee86vs
Try images 1500px width, optimize them using https://tinypng.com/
Regards