If you wan to be a tester of his maps, yea you have to join his patreon. Its worth the 20 bucks with all the knowledge you can obtain in his discord
Paying to be a map tester and the map being released for free when it's done and a map being behind a patreon paywall are two totally different things.
The first part of your comment is exactly what DR is doing.
I'm not going to pay to be a map tester. He needs to pay me to test his maps. I'll provide the testing services for a fee.