From my first hand experience designing these algorithms at Meta and running experiments, and listening to feedback from accounts, I would guess that you are not getting reach because your followers do not interact with what you post. In almost every case people call "shadow ban", the cause was occasionally an actual bug (code doing something undesired and unexpected) or far more often people posting bad content.

The ML is good enough to know whether your followers want to engage with political content. If they don't, Facebook will show them less of it.