Unfortunately the HAR file expired before I could take a look at it, sorry about that!
However, I think the main part of your problem is probably that you don’t use our CDN to serve your site’s content. Please take a look at this article about a better configuration for you in DNS that will allow you to use the CDN, instead of your current config, which causes all resources to serve from San Francisco, USA, on the west coast.
Since you use the bare domain for your primary custom domain (you can change to www by using the dropdown in my screenshot below, which is the easier fix compared to finding a new DNS host that is more capable so you can use the bare domain on our CDN), and you use the load balancer “A” record, this is expected by us - but I am guessing not intended by you.
Let me know if making the DNS change (or site settings) helps out!