What are the Limits of Orthodoxy? - Intro

I've been contemplating posting on this and other related topics for years

Part of my hesitation is the fear of maybe going somewhere undesirable. Of opening up cans of worms.

Also certain ideas needed to coalesce. And I now see 3 or 4 proposed threads as over-lapping and I have a more comprehensive point of view or at least a series of questions to wrestle with.

For background I would suggest reading the following material and related texts

First Dr. Marc Shapiro's works especially The Limits of Orthodoxy

Then Biographies of R Hirsch and R Breuer.
Much of what I have to contend with is a rehash of 19th century German Jewish struggles

The first issue to contend with is how much or how little dogma is needed to be Modern Orthodox?

Or

At what point does a Halachic Jew abandon Orthodoxy and enter the domain of EG "Traditional Conservative" or Orthopraxy?

And if we cannot define a precise boundary, can we approximate one?

It would be helpful to understand the distinction between the Hashqafah of the Hildesheimer Seminary vs. that of the Breslauer Seminary. Whatever material one can find will serve to answer this question

I'm planning to research this by soliciting opinions and analyses by those who might know this elusive boundary?

Shalom
RRW