What keyboard does Gosu use?

Not sure amigo, But tech does not make the man, Skill does. (And also the girth of his belt buckle.)

If you want to buy it for the clicking, just buy any mechanical keyboard with cherry MX blues

I believe he uses the Razer Ornata, but his mic turns down how loud and clicky it can be. Here's a sample typing test on the Ornata https://www.youtube.com/watch?v=FWtlhc9z76o

Before the Ornata, he used the Razer Stealth (2016) edition