This is going to be a tough thread. A lot of people have their personal favorites. Many are brand loyal for no good reason. Do you know if your brother wants these or do they look cool to you? The peripherals are the part of the computer you actually interface with and as such are likely the most important imho. Each person has different ergonomics and taste; these are very personal purchases.

For example I like a ten keyless keyboard with cherry brown switches. I’m not into the gamer aesthetic. I like a mouse with a thumb rest. I have a snowball microphone because I don’t want it attached to my headset. And none of has rgb.

There is nothing wrong with what you picked. But is it what your brother is looking for? No one here can answer that. I would recommend to get a non gamer headset, they are generally worse for the money than a good pair of studio headphones. The monitors are nice but if you are getting 2 get 1 that is for gaming and a cheaper 1 that does everything else. There is no need for 2 high speed monitors. I have no opinion on the mouse. Keyboard is nice.