is there a way of m,aking it so remove works with a automatically binded key like they have on builders sanctuary? so youd just hold your hammer out and press r?

There's no way to automatically bind a key on the Rust client as of a couple years ago.

oh right okay, but how does builders sanctuary go about doing it?

I'm not familiar with them and I'm not aware of any way, so it's hard to say.

ah thats okay but thank you anyway!

Plugins can detect pressing some common action binds like Reload. That is how other servers would do it. Can't actually detect R, so if a player binds R to something else, they would have to press whatever else they bound to Reload.