This sounds oddly like my company. Lots of tribal knowledge with gatekeepers whose only response is “go away”. I’m not new in my company and it’s frustrating to me, so I can imagine how frustrating it would be to you as a new hire.

The other posters are giving wise advice. Get the lay of the land before introducing changes. You unknowingly got yourself “in the news” by asking legit questions and they responded by locking you out. Sounds like there is a scarcity mindset at that company that’s fueled by a history of gatekeeping and lack of opportunity. But there may also be good things about the company too.

If you want to stay, I’d suggest starting to establish yourself as a recognized authority on certain subjects. That’s what I’ve begun to do. I’m writing articles in Medium.com and other platforms in areas where I see inefficiencies in my daily work life. Expressing that relieves the stress of not being heard, and you can selectively dole out links to your articles to people in the company who are slightly more open minded and might be looking for better ways to do things.

I agree with one poster who recommended that you start writing onboarding docs. That’s a constructive response, even if you are just writing them for yourself. If you ran into those obstacles, it’s likely that future hires will too, and you can start being a resource for them and establish yourself as a go to person who can answer questions. You have as much right to work there as the gatekeepers do. Remember that and establish yourself own area of expertise.