Well done @physics-o-mania - excellent paper.!!! There are many physicists over the last century who have done great things to expand our understanding of the natural world, however few achieved the prestige of Einstein - my personal favorite is Hisenburgh, and although not nearly as famous, the uncertainty principal is no less important to the modern era as E=MC2.

No single theory (before or since) has become so entrenched within our scientific paradigm as is relativity, and unfortunately I believe the future/history will likely show much of Einsteins theory(s) to at the least be "incomplete", and some aspects perhaps entirely "incorrect". Don't get me wrong - he's a "god" of men and in my top 5 greatest ever... However...

Even within Einsteins own writings, there was uncertainty (pun intended), and as he grew older he became so sure of his own genius that he even argued against quantum mechanics and proposed an alternate "hidden variable" theory to explain the "spooky action" inherent within quantum theory - unsuccessfully of course. Here we are 90 years later and quantum theory is the most successful and thoroughly tested scientific endeavor ever.
Einstein himself said about your example of gravitational lensing, that it was doubtful to ever be proven, and although he was the first to predict "dark energy", he almost immediately questioned its validity and referred to it as his greatest blunder.

As a student of all things "sciency", I have personally tried to wrap my head around why someone as brilliant as Einstein would be so unwilling to accept even his own assertions, and that extends to today's so called experts in general and special relativity - having this weird dichotomy where when considering the newest scientific discoveries of today, they are unwilling to change their perceptions with new developments - like Einstein and almost like the mysticism of the past - ie religion...