I've been thinking, what if we make a new building mode which works similar to something like Lego Digital Designer? Instead of walking around and pressing keys on the numpad we use the mouse, there could be a GUI with a list of bricks on the left side of the screen, you click on it and you can grab a brick, you can move it with the mouse, rotate by right click, and build by left brick, and move the camera around by pressing a key to go into orb mode, and then activate the mouse to build again by pressing M, I think this could be a fast way to build idk.
Wait no let me elaborate it better, okay, imagine that there is a command like /buildmode or something, and then the UI shows up around the screen, you still can walk around and stuff, but to use it you have to press that M button to use the mouse in-game, which then allows you to use the UI