Conditional loading #1

Do you think it's possible to load polyfills conditionally, as in:

if (
        'startsWith' in String.prototype &&
        'endsWith' in String.prototype &&
        'includes' in Array.prototype &&
        'assign' in Object &&
        'keys' in Object
    )
        // avoid punishing modern browser users
        return;

import("core-js/...")

The trick being that all of Next.js scripts would have to wait for this step to complete (either skipping polyfill loads or waiting for core-js imports to complete.

This was easy to do without Next, however, now it seems quite tricky.