[FLUX-YOU]

>I am asking this because I was recently asked by my manager not to give talks in really difficult to get in industry events, despite of getting an acceptance.

This is dumb. They are just afraid of losing you, possibly because you are under-compensated and they know it. Conventions are networking opportunities and you'll likely get approached if you make yourself available at a convention like this.

There may be a corporate reason (you showing up as an employee at a questionable convention), but you should have the freedom to go as an individual and not represent the company.

If my manager asked me to do that, I'd be on my way out.

As far as managing better managers goes: be honest, admit mistakes, give suggestions for improvement, and there is almost no management to be done. If they begin to rely on you too much without giving you something in return, talk it out to see if they can spread the burden or give you more pay.