I don't like the casino, it's very tight and difficult to get around it. It's also very smokey inside and the filtration system doesn't do s good job of cleaning the air.
The 888 taxi company has a shuttle right outside the terminal which does the same thing. No reservations are needed and they run about every 15 minutes. It's about the same price or a few bucks less than Royal. I've used them many times, the last time being last week, and never had an issue.
I always book as soon as the new itineraries come out. This way I get the room I'm looking for. I've got 15 booked going through March 2025. I'll be on the Anthem this Sunday and expect to book one and maybe two more thru Next Cruise.
It's like booking a cruise. If the price is acceptable to you, book it. If not, don't. I don't think there is any kind of taxi commission that sets rates. It's more like what the market will bear.