Could you please identify your source for that?
https://www.google.com/search?q=rnc+trump+joint+fundraising+agreement+pact
Thanks but none of the search hits saying anything about the RNC not being allowed to fundraise on their own. Again, how did your reach that conclusion? The purpose of joint fundraising committees is basically to allow campaigns to combine their efforts to raise money more efficiently.
Unless you have specific information to the contrary I don’t see how this prevents the RNC from raising money on its own.