I like to use an app for auto-compressing product images, collection images, and your Assets folder. Then manually compress images embedded in blog posts + images you upload in the Customize Theme section (apps can't access those).
Here's the method and tools I use: https://speedboostr.com/how-to-compress-images-on-shopify.
Your site (at least the home page) look pretty good from an optimization standpoint. 3rd party app widgets like the chat and the trust pilot usually cause some page lag, chat apps are good for engagement though so if it's working well for conversions it's probably worth keeping.
You also have a console error I think related to that chat widget:
Sometimes these errors cause slowdowns, sometimes they don't. I would fix it if you can though. If you're not familiar with how to work with the console I wrote some tips here: https://speedboostr.com/finding-and-fixing-server-errors.
From a conversion optimization viewpoint, couple things that stuck out to me are no logo and no info (or at least easy to find) about the brand. I would make conversion rate optimization a priority before performance since your site is already pretty lightweight.
