The latest What If touches on it without coming out and saying it.
In our universe, the fixed point would appear to be Strange losing the use of his hands. In the show, Alternate Universe Strange tries timeline after timeline to avoid his fixed point only to discover that messing with one can destroy your whole universe.
As for Loki/Kang, they need to set some rules about it. Are we looking at timeline Kangs, with an infinitude of decisions that all lead to a Kang who's more or less the same (a human descendant of Reed Richards and/or Victor VonDoom) except for variations in personality resulting from choices of his own along with those of people close to him.
OR
Are we working with alternate universe Kangs. An essential-oil Kang, a gumdrop Kang, an amorphous blasphemy Kang, a Kangaroo Kang, a silicon-based Kang, a Vulcan Kang, etc. etc. each the denizen of a whole universe with its own laws of physics, its own infinity of timelines, its own whole-damn-shebang.