Sorry GK. Okay, ""How it is possible to come up with a consistent pov if one believes everything is true/false? (tralse?). The outcome seems to be one's pov is there is no pov." I believe I answered this... there is a point-of-view and it is probably unique to every individual.
Now the question is are they true of false or somewhere in between? I do not know (or think) that any single pov is true because a lot of what we believe is not testable or falsifiable (which puts all povs in the third category in my opinion). Many (if not most) povs are clearly false... "g!d created the world in seven days" or "whites are superior to other races" and other such dogma or ideology is both false and dangerous.
Those I referenced in the previous post (Einstein et al's povs) have more of a likelihood of being correct than mine or yours.
As for your second question, no, relativity has it's own true and false theories. Einstein's theories fly in the face of modern measurements, but his math is sublime (even if incorrect, see "Cosmological Constant"). Similarly his view of a "steady-state" universe has (finally) gone the way of the dodo bird. Similarly, the cosmological thesis of the big-bang (in the sense that was it one instance, multiple parallel universes -- a neat way around quantum theory, or a cyclic set of instances, much like Indian philosophies and religions -- and given very strong math by Wheeler, Penrose and Heller) which is one of the basic ideas of post-Einstein relativity can be see as both true and false.
A lot of people think Einstein delivered General Relativity in a fell swoop. They do not realize that Whitehead had a mathematical identical theory that was different. They do not understand that until Wheeler began teaching it and enough physicists finally learned the metrics it (about the 1955 time frame) was left untouched. Nor do they understand that at the deepest levels (like M-theory or cyclic universes or multiple universe -- all part and parcel now days of General Relativity) that it is perfectly consistent to argue for the truth and falsity of these topics. Why? The math yields the same answers.