Samsung has released a One UI beta for Galaxy S devices and also a list of devices that will be compatible with said update¹
This update, once released, will bring Android 12 to Samsung devices... that are on the list of supported devices
My device (Samsung Galaxy A20) is not one of those devices and while I really do not care about upgrading; other people might do.
Google apparently says your device needs to be a new standard which is called "performance class 12" to use Android 12 effectively, which involves storage speeds (mostly irrelevant to an OS except when gaming or server use), processor performance (the one that makes sense), screen size (my screen is literally the size of my phone) and camera performance (why does this impact my operating system?).
All incompatible devices are therefore called "performance class 11" which is a "subset of performance class 12" and also calls them "older, but highly capable".
Riddle me this, if a device is "highly capable" then how on earth is it not eligible for the upgrade?
A phone compatible with One UI 4.0, the Galaxy A51, is barely different from my phone!
They have a 0.1 inch (1.5 cm squared) difference in screen size, a difference of 1GHz in the more powerful cores while both still having octa-core (???) Exynos SoCs. The only big differences being the camera
So my device is seen as "older, but highly capable" because the camera is inferior so it can't get Android 12? That's stupid.
 Mine not being one of them.