TLDR: Where can I find a list of Unifying-compatible keyboards?

And why on earth did Logitech start removing this capability from many keyboards? It sure seems Logitech has a pattern of producing products that get good reviews, then silently replacing them with worse variants. Having four different incompatible kinds of wireless receivers is a big part of that.

Background: A while back I grabbed a MK270 combo. I'd seen good reviews for the keyboard, including ones that mentioned the benefit of Unifying. The included M185 mouse was only passable, and it seemed inevitable that it wouldn't last, but I figured I'd replace it with a better one down the road.

Sure enough, after about a year the mouse was toast. (Main thing was that you couldn't click and drag, it would act as though you'd let up on the mouse buttons.)

One of the better variants of the m720 was on sale, so I picked up two. Only afterwards did I realize that the keyboard and mouse weren't compatible because Logitech silently switched the MK270 so it was no longer Unifying compatible. Disappointing, and using two receivers was a waste of scarce USB ports. I have no idea what replacement mice I could have purchased that would have been compatible with the keyboard's receiver.

I need to outfit another mini PC with a wireless keyboard, and this one has even fewer ports, and will be in a spot it's inconvenient to put a hub, so I'd really prefer to not repeat the same mistake.

I don't know whether I can trust Logitech's individual product pages as to whether things are Unifying compatible, due to the different variants. And over half the Logitech wireless keyboards or combos you can find on sale are no longer listed in Logitech's product list, so you have to go searching for individual models' pages.