WinRed is RNC. I almost gave earlier but would rather give to DJT himself.
Perhaps they run it. They certainly have enough ads on there that try to entice you to give directly to the RNC, as well as give to individual campaigns of other incumbents such as the high-profile GOP Senators who were considered endangered this year.
But other than the direct links to RNC donations, you can give to individual campaigns like Trump's, so I'm (hopefully) guessing that a high proportion of what you give to an individual campaign goes to them, and very little, if any, is the RNC's "cut".
I tried to bypass the RNC too. I couldn’t easily find a way to donate JUST to Trump directly. :(