Politics is everywhere, people will fight you not on technical merit
  but because they want to claim responsibility for something even
  if its inferior to the product you could build - if you don't
  have the support to push through this I suspect you'd get stuck here.

In my meager experience this is not unusual in large(r) organizations. At one point at megacorp there was a big push to get me to buy into some atrocious docker orchestration thing as I was part of a high velocity team. There were two teams working on this internal monstrosity and each manager was quite happy to promise entirely contradictory things to promote their own status within the company. I've never been so fast to turn someone's name into a verb.

Another shining moment was when the security/compliance department cobbled together a Hashicorp Vault proof-of-concept and lobbed it over the fence at one of the ops teams. The ops team didn't have the bandwidth to deal with it and the security team refused to maintain it. It was ridiculous enough that veeps and directors got involved.

  Corporate structure is confusing because everyone's titles are massively inflated.

This has been my experience at most tech companies I've been at.

  Claimed to have internal open source in the Division I interviewed for (didn't expect that).

Careful what you ask for. ;)