Hello,
Your checkout layout looks in another way (we created in theme) -> https://prnt.sc/Z-2eQzTGBhTN and origin design -> https://prnt.sc/IzhEgg3R3hxG (there are such forms for login/coupon as you see)
After we checked your plugins we found that WooCommerce germanized was the reason of such issue -> https://prnt.sc/e0MgeQuo-qCO (when WooCommerce germanized is disabled)
You should definitely contact with Plugin’s author and tell them about such issue, because it seems they already had some issues with other popular themes (you may check next screenshot where it is shown that they had to add a few extra files for compatibilities -> https://prnt.sc/PIDHIK8J1WUC ). In such way, they could add compatibility with our XStore theme as well or could provide us some code snippet for our theme to include it globally from our side (to make such compatibility with them inside XStore theme).
Regards