@KieranR So can you just confirm that there’s nothing that can be done our side in the Theme or otherwise to minimise and cache /checkouts/internal/preloads.js?locale=en-GB file and that this would be a Shopify server side issue?
It’s possible, you could download the file. Then save it into the theme asset files, then use a {{content_for_header}} customization to exclude the script tag from the header, then manually re-include the file as a custom script tag. Shopify will then run it through the normal theme .js processing which includes a way to minify.
But in my view none of this is worth doing and it will probably end up breaking more stuff than you set out to fix..
How are you discovering this “issue”? Is it also coming from a SEMrush audit report or similar?