from my perspective all of the above desktop environments are moving towards Wayland support in a relatively good way. We don’t like GNOME because of previous privacy concerns, and we don’t like KDE because of resource consumption. The other two we could live with, the only reason we can’t live with XFCE is because the developers aren’t all that fast at porting since they have lives to live too.
I thought about Budgie, but 10.9 only has preliminary (i.e. experimental) Wayland support, which insinuates it will probably be as rough or worse than XFCE in Trixie.
I’m not sure how much of this is unfounded supersition and how much of it is reasonable wariness, but Kylin and Kylin-related projects scare me. Kylin (which openKylin is the open-source variant of) ss state-funded by China as I understand it, and China’s current government is, to put it mildly, not particularly well-known for its commitment to privacy or user freedom. I don’t necessarily mind using software that is Chinese in origin if it’s well-respected by the global community, but something state-sponsored… it’s kind of like using encryption algorithms designed by the NSA; even if they look good on the surface, there’s probably a backdoor. I fear the same could be true here too.
This fear is further enhanced by the fact that another Linux desktop environment with ties to the Chinese government, Deepin, was removed from openSUSE because of a mixture of semi-malicious packager behavior and the code being a security disaster under the hood. I don’t have any particular reason to trust Kylin more than Deepin, and wouldn’t be surprised if the code was similarly horrible.
Aside from the privacy and security concerns, I’ve used Kylin very briefly doing testing for Ubuntu, and found the English in several spots to be too broken to be comfortably usable. Since Kicksecure and Whonix are primarily targeted towards English-speaking users, I don’t think this would be a good fit.