Amongst guards that play more than 25 MPG, Brown is 13th in the league in TS%. That is pretty amazing given where Brown came from when he entered the league. Very impressive if he can maintain it.
So instead of minutes per game I looked at guards and usage. Among guards with a usage of 21% or more Brown has the 6th highest TS % in the NBA. The five guys above him are Harden, Booker, Doncic, Lillard, Fournier and I would say Brown is clearly the bester defender of that group.
Or if you consider him a forward and use the same restrictions (throw in 18 or more games to rule out some small sample guys) he is also 7th in the league behind Giannis, Doncic, George, Bogdanovic, Fournier, Gallinari. He's probably the third best defender in that group and 2nd youngest.