Why don't I follow Modern Orthodoxy(MO)/Rationalism/Academics ...?

As they seem to have some answers to the questions that I am raising.

Before I answer I want to provide a minimalist definition of what I mean when I say MO/Rationalism/Academics
1. Engagement with the world and secular culture
2. Belief in the scientific/academic process, for example, they accept the fact that the world is billions of years old and strive to reinterpret the beginning of Breshis or allegorise it
3. Observe mitzvos

I have a number of issues with this approach the biggest being the following. I would ask the following question. Do you have any red lines that you will not cross? Is there something that you believe no matter what, namely, mass revelation at Har Sinai?

If the answer is yes, then in essence they are being hypocritical and inconsistent. The same scientific/academic process that says that the world is billions or years old and that a global flood didn't happen says that a mass revelation at Sinai didn't happen. All of the experts (historians, archeologists, etc.) say that the story of 600,000 men over the age of 20, 2-3 million people in total,  leaving Egypt going to Har Sinai and then wandering in the desert for 40 years simply could not have happened based on the archeological and historical evidence. Additionally, all of the experts say that the Torah was not written at the time of Har Sinai but that it was actually written much later by men. You can't believe in science sometimes and then not believe in it when it destroys your worldview. In essence they have no answer to the essential questions of Matan Torah, mass revelation, Torah from God.

If the answer on the other hand is no, you have no red lines, then what is left if you reject mass revelation at Sinai? If there was no mass revelation, the Torah was not given by God but instead was written by man, then everything is man made. This approach destroys Torah Shebaal Peh and specifically Gemara. The gemara on almost every page derives halachos from various derashos of extra words, extra letters, the same words (גזירה שוה), etc. If the torah was written by man then these are all worthless and have no meaning. How can you make a derasha by asking why is this ו extra when the whole Torah was cobbled together from different pieces by an editor. Of course there are extra words/letters but not because God put them there to learn something but rather because the editor didn't do a good job. This answers the questions by removing everything. Why keep arcane halachos like wearing boxes on your arm and head every day when it was made up by men? All that is left is a bunch of platitudes about tikkun olam.

Additionally, when I was learning in yeshiva and even after, the Brisker or conceptual approach to learning really talked to me. I got tremendous pleasure from hearing shiurim in this style.  R' A Lichtenstein said the following about the Brisker derech:

R' Chaim espoused conceptualism because he could not imagine the words of God as a pedestrian amalgam of incommensurate detail. There is a power, majesty, and grandeur in Torah conceptually formulated, that a patchwork of minutiae largely folded by ad hoc pragmatic considerations, simply cannot match

At the time I believed this wholeheartedly. Torah was brilliant and everything was so logical and fit in together. However, as I got older, I realised that as brilliant as the Brisker approach is, it is not historically true and is certainly not how the Tannaim and Amoraim, and even the Rishonim approached Torah. The שרידי אש in both a teshuva and a published letter says that R' Chaim's analyses of the Rambam are not historically true. It is clear that the Rambam's derech was not R' Chaim's. All you have to do is look at the Teshuvos Harambam where he deals with some of the issues/contradictions. The Rambam never gives any lomdus to explain his psak, rather he gives what we would call Baal Habatish answers. He had a different girsa in the Gemara, their copy of the Mishne Torah was wrong, he made a mistake, etc. Not once does he employ anything close to Brisker loads.

I recently read a fascinating essay about Brisk and 19th century legal philosophy, Legal Theology: The Turn to Conceptualism in Nineteenth-Century Jewish Law, where the author see parallels between the rise of the Brisker derech and similar trends in the field of law in Europe. From there you see clearly that the Brisker Derech arose n the 19th century at least in part because of what was going intellectually in the 19th century, and that the Brisker Derech was a new way of learning Torah.

The academic approach on the other hand, believes that the Talmud Bavli is a compilation of various שמועות of אמוראים cobbled together by many editors over many דורות; probably never “officially” completed (except in hindsight); not necessarily comprehensive or even self-consistent. There certainly is no overall logical system and many disputes are simply disputes about how things were done. For example, the Rishonim argue about how high someone must pick up an object to acquire it, one tefach or 3. The Brisker approach is to make this a dispute about the nature of a kinyan, does it actually transfer ownership or is it simple proof that you acquired the object. While this sounds great, the more probably explanation of this dispute is based on the prevailing customs in each locale or that there is no underlying principle, each side simply states what seems intuitively correct. To believe that the Tannaim/Amoraim or even the Rishonim thought in 19/20th century conceptual terms is simply not credible.  I am convinced that the academic approach is the historically correct one but it robs the Torah of it's majesty and makes it into a set of obsessive details that don't fit together.