Most apps on the list are lemmy apps, meaning they don't work with kbin. Artemis is specifically designed to work with kbin, not sure if or when any of the other ones will go in that direction or become interoperable as there are some challenges with the kbin API at the moment. Having said that, a new API is in the works (https://codeberg.org/Kbin/kbin-core/pulls/357) so things should get better with time.
Some of the apps are in a very early stage of development so it may happen that they adjust OS availability and platform support.
But I get it, without an official API, it's a lot of work to get one going. I just refuse to use Lemmy, so I'm committed on getting a Kbin app ASAP. We're just about to have alpha.1 build ready and it's pretty darn usable.
EDIT: me not going w Lemmy was due to devs. I still think it’s a viable platform for the fediverse, especially with all the instances out there besides theirs (and being open source). Kbin being completely separated just felt like the right choice for me when picking between the two.