I thought the whole point of Android is to make a curated touch friendly Linux experience. If you want a more traditional distro, wouldn't a touchscreen laptop (yoga etc.) be a better choice, if only for x86 support?
The Surface Go 2 that the article is about, is an x86_64 device - I recently aquired one and it's really quite nice with Linux in my limited testing. The biggest difficulty with a standard desktop GNU+Linux on a tablet is that most distributions are not optimized for easy tablet use - KDE Neon User Edition e.g. does not come with a virtual keyboard preinstalled.
On Yoga style laptops: Well, they are easier to get started with, but they often are quite a big bigger and having those keys on the back all the time... It's doable, but if you want a "nice 10" tablet" experience these devices are just not what you will want: Too large, too thick, too heavy.
Ubuntu 22 on a Lenovo X1 Fold gave me the OSK without installing anything - though the touchscreen was not supported by default, the driver is under work cf https://github.com/quo/ithc-linux
But by doing that you get to maintain all the malware that comes builtin on the mobile OSes.
The OP wants to replace the kernel. But most mobile devices use very specific hardware that do not have drivers compatible with the standard kernel you get from your distro. Technically, the manufacturer should have to supply you the source of the drivers they use (so you could port them), but good luck enforcing any right of yours against a large company on the legal system (any country's one actually).