I like those who have the courage to tell me on my face that I am wrong. And I will not be ashamed of accepting my mistake, as only that will lead to my true destination, truth. I am in the pursuit of truth and I will not let anyone come on its way, not even my ego. I agree with your observation that many use multiple techniques to provide their point and many times they even contradict themselves. Althought I can’t comment on your observation on anyone specific. I have high regards for my Guru, Pt. Sanjay Rath and in my view he is very scientific in his approach.
Also, another thing, just being able to explain things after they have happened, does not mean that one will be able to predict, using the same approach. This is because, an event can be caused by many many combinations in a horoscopes. Just narrowing down to few specific ones is always difficult, which is what happens when one analyses a horoscope from a future perspective. Also, future is always possibilities, hence one can’t claim with 100% certainty that, that is what will happen. One can only talk in terms of low or high likelihood.
Last but not least, like a Doctor, an astrologer, should keep researching, as with the change of times, the interpretation should be adapted. For instance, in ancient times, multiple marriages were allowed, now they are not. Hence, the interpretations need to be adapted based on the time. Thus, the desa, kala and patra becomes important.
You have brought out some important challenges in Jyotish and its limitations. If you are objective and “disciplined” in your approach, one day, you will be successful. For instance, when you are analysing the dasa of an event that has already happened, don’t look at the Mahadasa and the Antardasa directly and explain, why certain things happened in that period. Behave, as if you don’t know when it happened and trying to figure out the period based on the analysis of the natal chart, as you would if you analysed before the occurance of the event. Then, you can validate, how accurate your analysis was. In some cases you will fail. But then you can uncover why you failed. What went wrong with your analysis. Hence, being objective and disciplined in our approach is important. With each failure we learn how not to fail again :).
I would also recommend that you remove the birth details from a public place such as this, as this is not a good practice. There are certain things which are best kept as private :). You can give this to someone if you want to get a private consultation.
Wish you all the best!