Prevention is the best cure for that - get a squeegee and hang it by your shower, and have a rule that if you get the glass wet, you get every drop of water off it. Some of the shower sprays just reduce the surface tension to stop water sticking (i.e. they are a similar preventative measure to just wiping all the water off) - they only work if you use them every time (but wiping with a squeegee is easier, the reason those products exist is selling a consumable you use every time you shower is more profitable than selling a squeegee).

If over time, you repeatedly get it wet, and don’t let any liquid dry on it, you’ll eventually leach out all the scum (most Melbourne water is relatively soft - low calcium - so just water works eventually). If you really want to accelerate it, try something with oxalic acid in it, which will strip calcium from limescale - but repeated cycles of tap water and squeegee will eventually get the same result.