Just a note (ok rant), prestashop implementation of guest checkout is WEAK. Returning customers who previously checked out as guest can NOT checkout as a guest again, leading to confusion and a lot of visitor friction. Today many 'modern' websites do not even collect password at checkout...that is the trend.
I have checkout module I use on client shops, because the out of box checkout is better than anything on addon's, they have not been updated to reflect moder checkout.
https://prestaheroes.com/collections/all-modules/products/checkout-pro?variant=40653350011087
the real purpose besides 'above the fold' checkout is that the module also allows 'unlimited' guest checkout with same email. doh!
I'm considering to cut out just the allow guests checkout logic and make it a standalone feature.