I did what you are doing. I learned about the sport before joining it. You will run into a few problems. People will judge your personal fight results and use that to give credit or discredit to your knowledge. If you didn't wrestle and repackaged advise from sanderson people would see you as an unproven outsider and discredit you. Often want to wrestle you and after beating you discredit your efforts cause they them self are better and they them self haven't created a writing project.
Before i got into mma i was a book worm. I read like 12 hours a day some times more just drinking tea and coffee. While it was a great time in my life i was weak, soft, and docile.
I became interested in MMA and started consuming content. Mostly instructional. Sure when i went to a gym i was weak and soft and out of shape but my brain was capable of understanding what people were doing. I knew the difference between the omo and the gogo plata. While i could teach the move to someone, i couldn't apply it live on anyone.
Same with anything i learned. I'd learn from different resources put what i learned on paper. Then I'd condense what i learned. Publication first took place when i let others see my work. You can do the same thing. The easier way to not get rejected is to give the information to people not in the sport. Generate interest with people who haven't yet built an ego.
A quote. Something like. "Its easier to teach a novice who knows nothing about something complicated then it is to teach an intermediate about something basic."
The people who resist you or become defamatory are those intermediates. Accept you are talking to the wrong audience when they stop being helpful. Direct your attention to people unrelated to your content and try to inspire them to take up what you are promoting as a new hobby.
You want to study take down defense. great. don't expect to influence wrestlers in the community, Expect to influence people to join the wrestlers in the community.
Follow that mentality and you shouldn't quite when people try to get in your way.