Without seeing a read-only link, there’s no way for anyone to assess your build to see easily how you’ve built the site.
There are many threads on the forum where people discuss PageSpeed Insights. It is very possible to get good results within Webflow.
Without doing a lot of digging, here are a few quick things that will help
In the styles manager, click cleanup as you have 117 CSS classes that you are not using
some of your images are set up as background images. These are not delivered with responsive size tags by Webflow. Change these to image blocks.
You are using video content. Videos take up a lot of bandwidth. Your site is about 32MB. Needs to be much smaller, especially for mobile.
It looks like your website is needing to download quite a lot of scripts from Wix before it can load (this is probably causing the white screen). If you absolutely must use third party scripts, either add them to the body tag instead of the head or make sure that you add async to the script tag so it doesn’t block page load. EDIT: I think this may have something to do with the iframes you have in the hidden embeds.