Anything rotated by a rotation action will rotate around the rotate parameter center point. Move the parameter so it is at the center of the triangle and your text will rotate within the triangle.
Similarly, a scale action will scale relative it's parameter's base point unless it is set to 'independent'.
You really should not ever place the base point parameter anywhere other than the 0,0 point in the block unless you have a very good reason for doing so. It can cause problems. Instead, adjust the linework/parameters/actions so that the base point is at 0,0 and where you want it relative to the other objects within the block.
If it were my block, I would center the triangle on 0,0. I would place the linear parameter base point at 0,0. I would place the rotate parameter base point at 0,0. There is no need for any constraints. There is no need for the base point parameter.
