Is there somewhere in Thailand or Vietnam I can have my X-Box HDMI port repaired?

The link to get the repair started is here. It's common practice to send it in no matter where you are.

https://support.xbox.com/my-account/warranty-and-service/getting-your-product-serviced

Hi,

I think the best way is to buy a new hdmi cable for your xbox i don't know where you can repair it maybe use google and it will usualy shows the nearest location where you can repair it

Microsoft / Xbox has its central certified service. It is not excluded that he might have some service in your state. If there is no service in your country, and you still have a warranty console, you will get the labels from technical support to send
a package that you will not pay. Through UPC or another delivery service in your state, you will send your console to the nearest service. And within three weeks you should come back with a repaired or new console.

connect your x box with the hdmi and you can buy a scart convertor thingy with the red white and yellow ports

The fact your XBox is reporting the TV as being non-4k suggests a setting somewhere or possibly the cable itself...on my One X, sometimes it decided my TV wasn't 4k and displayed 720p and it needed the HDMI cable being unplugged then plugged back in.

Are all the HDMI ports on your TV both 4k and HDCP2.2 enabled? I only ask as sometimes not all HDMI ports will have all features enabled. What TV model is it?