SOLVED - kind of...
I contacted the support email address on the XMG website, but after a few days, with no reply, I found a Reddit group for XMG laptops and there was a user there called "besteware", saying they were the official support for Clevo/Schenker/XMG computers. I contacted them.
They replied quite quickly, but said because the laptop was so old, they no longer supported it. Sorry.
Then, I had a flash of genius! ๐ก I rarely every use the [ ยด ] key that puts accents above letters, so... I moved it to where the S should be. Et voila! I can now type half-decently again!
The later that day, I get an email from XMG support telling me how I can order parts...