I did this repair just a few months ago on my 3DS XL. Do you know if you still have all the parts, like the hinge and the metal tube/washer thing?
I purchased my replacement faceplate off of eBay, and I cared more about form over function, so it’s white, while the rest of my system is gold. It works for me, and took me about an hour from start to finish. and it’s been holding strong ever since.
If you are willing to pay for postage, I’d be more than willing to assist you with this. I am new here, So I don’t know if you can send a PM, but let me know if you are interested and we’ll sort out the details.
Best of luck!