@dafangefull before thinking about replacing the USB-c connector, go through the answers/comments of this question USB-C port not charging with power delivery See if that might work for you as well.
If it does not, then you will most likely have to replace the port. Of course, for that you will need to disassemble it and then finding a replacement port. Use these guides Asus ROG Ally to work on it. This task will also require some decent soldering tools and skills. Let us know what you find out.
Let's see if our game console guru @dan0 has some other possible solutions for your Ally's issues
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