Wow you should really consider politics. My BS meter is off the charts. Last September I started working on making a port to Android for a game engine. The first step was to create a GLES3 backend and then to make it work on Android. So the first 'sprint' took until January and the second until mid-February. Tell me exactly how do you write user stories for an OpenGL backend? It either works or it doesn't. There is no in between. There was nothing for me to show right until the end when I started getting things on screen, fixed a few last bugs and there it was, working. Literally, until the last few weeks there was nothing on the screen. If I had a client that would request a demo every 2 weeks I'd have been fired long ago. Luckily it was an open source project so there were no morons there who used Agile or daily stand ups or poker planning or other BS.
Some things take a long time to be made. There is a lot of pre planning, a lot of execution, and a lot of bug fixing. There is no way of iterating this stuff every 2 weeks. Unless you really want to get a lot of churn and make the project take 10 times longer while I create BS mini projects in order to show you progress at every 2 weeks. It either works or it doesn't. No in between. That is why planning is good, it tells you what you should do next. Also, you need to get it right, because you don't want to get the backend working 6 months from now and discover that you didn't need it. Don't iterate, think it through really deep because you probably get only one chance. Don't skip the deep thinking part. This is your make or break part.
Still agile people don't want to accept these things...