Do you have real suggestions on which part of the code do we need to improve?
Top issues of the GTmetrix report are not related to theme code https://prnt.sc/26d4x8f but to your page content and server settings.
Also, I see some failures from Paypal in the Waterfall Chart https://prnt.sc/26d4wnr It also affects the page speed, so fix that.
We don’t have any additional options in our theme to speed up site. So, contact your hosting provider to make the site faster from the server side.