USPS - How do I Update OpenMage to Use New API's and New shipping options?

[ClassicComics]

I want to get the new USPS API's working on my OpenMage install. I am currently using the old webtools ones currently set under Configuration/Sales/ShippingMethods/USPS in ADMIN. Where you have spaces to enter Gateway Url (http://production.shippingapis.com/ShippingAPI.dll) and Secure Gateway URL (https://secure.shippingapis.com/ShippingAPI.dll) and a space for User ID and Password. However, a while back they renamed a bunch of the less expensive shipping methods and deprecated them, so I am really only offering Priority Shipping right now, which is not ideal.

They are also moving to all new API's and eliminating all of the old ones come January 2026.

I would just like to get everything updated and correct with all of the options and the new API's. I have been digging through the USPS documentation, and it's been a bit daunting so far. I have already received new credentials for the new API's and login info for the API Developer Portal section. I have also had several email conversations with USPS Webtools customer support. That ultimately wasn't very helpful to me at least.

What is the easiest way to update OpenMage with the newest USPS shipping options and new API's? Is there a new web address I can replace the old one with for the Gateway URL and Secure Gateway URL? And just put in the new User Id and Password?
And after speaking with USPS I'm even more confused about that because they said I should have a Consumer Key and a Consumer Secret instead of User Id and Password for the new API's, but I don't think I have seen these in any of the stuff I have received so far.

Is there no way to do this directly with what exists currently in OpenMage? Or do I have to use an extension made for this, or attempt to build one in the developer portal? Any and all help would be GREATLY appreciated. Maybe a link to a tutorial or some instructions I can follow that make sense to me on how to directly make the changes in OpenMage? Or an existing extension that does this?
Thanks in advance for any and all help with this!!