I am not sure of the dynamics behind the APYs, I have assumed it can vary with the time but I dont know how much they vary, hopefully someone with more experience than I can answer the question.
Also, when I mentioned Ether staking I meant using Ether to become a validator within Ethereum blockchain itself, in that case I believe there is a clear difference between staking on a centralized service like a casino and staking to validate transactions in the advent of Ethereum 2.0, getting more Ether as reward.
I feel like with this you're drifting away from the theme of this thread. It's about investing in casino tokens, not staking ETH.
Casino tokens are risky just like NFTs and new altcoins. They are as risky as buying Luna at the bottom, but you can always earn on this move like people who bought Luna made some money when it pumped a few days ago but it doesn't prove that Luna is a good token or that investing in casino tokens is a good idea. It's gambling.