> Kant used Newtonian assumptions about the time and space, treating them as absolute, and treating them not as properties of physics but necessary preconditions for us being able to experience anything.

Ok... this is non sequitur. It really doesn't matter that time moves at different speeds for any of Kant's philosophical positions. 2 people could be traveling at 0.5c and 0.00000001c and that makes no difference in Kant morals on how they should behave.

And, practically speaking, unless there's a drastic development in propulsion the only bearing relativity has on day to day life is making sure the GPS works correctly. It is, otherwise, completely non-impactful to anyone beyond astrophysicists.