Fixing Magento 2 Checkout Page Issue (Base Url broken)

I'm experiencing a JavaScript resource path issue on the checkout page of my PDQ Magento 2 store. The page gets stuck on loading (spinner), and several JS files return 404 errors.

The incorrect file paths look like this:
- /checkout/mage/bootstrap.min.js
But the correct path should be:
- /static/frontend/revsupply/pdq/en_US/mage/bootstrap.min.js

This issue:
- Happens only on the PDQ checkout page
- Does not occur in local development
- Seems related to RequireJS baseUrl misconfiguration or server path injection

What I've Tried:
- Verified static content is correctly deployed
- Confirmed no issues in env.php or core_config_data
- Compared against working Coyote store setup
- Suspect reverse proxy or server header manipulation (X-Forwarded-Prefix, etc.)

What I Need:
A Magento 2 expert to:
- Identify and fix the misrouted JS file loading on checkout
- Ensure checkout works properly with all scripts loading from correct paths

Ideal Skills and Experience:
- Strong expertise in Magento 2
- Experience with RequireJS and JavaScript loading issues
- Familiarity with server configurations and reverse proxy setups
- Ability to analyze server logs for troubleshooting