My own personal conspiracy inkling is that flat earth theory is a deep state psyop created for the express purpose of discrediting more valid and damning theories (because it's certainly used that way)

That is a good instinct. It is certainly used that way, but it is not the psyop’s primary purpose - it’s a fringe benefit of it due to its success.

The primary purpose of the psyop is to prevent any earnest discussion or research into the valuable subject. It does this a variety of ways, perhaps chief among them falsely conflating contrived offensively stupid ideas with it and those who would dare to study it. In my view it is a case of “the woman doth protest too much”, because there is no other reason to spend so much money on an advertising campaign (i.e. psyop) to convince people an already ostensibly stupid idea (the world is flat) by default is too stupid to ever bother looking into...

I'm always open to more evidence

I encourage you to join us on flatearthresearch to discuss such evidence, methodology, and generally exchange our views!