Don’t use the stock kernel. Use the HWE one if you want newer hardware to work on Ubuntu and its derivatives like Mint.

Or try a Fedora live-usb and see if it works with the newer kernels.

My newer hardware is circa 2015.

Is your 2 in 1 one of those baytrail cpus with some atom z sonething? If so, they're really problematic with linux, since they were released, due to some obscure stuff in their soc. I remember even people who formatted and reinstalled windows losing functionality.

HP Elite x2 1012 G1. Has an Intel Core M5 processor.

Frankly. I was expecting to spend hours getting this thing in a useable state, but Mint had everything working on a clean install except for the the volume button on the tablet itself and the function buttons on the KB. Honestly very impressed. If I did a clean windows install I would be pulling drivers from HP and installing them for about an hour to get this level of functionality.

I figure a quick script or something that turns on the On Screen KB when the physical KB isn't detected is possible, and that I can manually config the volume buttons and keyboard shortcuts. Then this tablet will have all its features working.

Oof. I didn’t realise that and assumed it was some new fancy hardware.

My original comment still stands though. The HWE (hardware enablement) kernels on Debian and its derivatives like Ubuntu/Mint are your best bet when it comes to new or obscure hardware. They link extra drivers into the kernel and have patches to fix issues you normally wouldn’t encounter, basically stuff they won’t include in the mainstream kernel for the sake of stability or whatever. I always used these kernels before I migrated to Fedora because the extra keyboard buttons on my laptop wouldn’t work otherwise.

Thanks for the advice. Much appreciated. I don't mind old hardware. It's a rescue. Poor thing was in a disposal bin, and I gave it a forever home.