Hi! I’m a user of the older MatePad 10.4 from 2020 with the Kirin 820. The device still works great. nowadays I gave it to my dad. MatePads, in terms of build quality, are a lot like iPads very premium. Mine even looks similar to the 10th iPad.
Unfortunately, it only got Android 10, but keep in mind that Android is a very fragmented OS, so most apps still support a wide range of versions. You really shouldn’t worry about compatibility for at least 4 more years.
And keep in mind that the 12X is a more premium device, so maybe Huawei will update it to at least one newer version of Android