I wouldn't need to use it for gambling directly. I could use it to rebalance funds between wallets that I use for gambling, without paying 2% for a mixer.
Doesn't matter. Coinbase and other exchanges will track coins backwards and forwards multiple transactions. If coins are going from casino -> wallet A -> exchange -> wallet B -> casino, then the exchange will rapidly pick up on that. Even if you add multiple hops in between casino and exchange, once you've done something similar a few times your account they will pick up on it. If you are using an exchange which looks down on gambling and casinos, then your account will be flagged up and frozen, and expect any coins you have on the exchange to be inaccessible.
Further, not all mixers charge 2%. ChipMixer can be used with any fee you like.
If I use Wasabi coinjoin I get directly linked to one particular rando who might have dirty coins, which is not as good as getting clean coins from coinbase.
Then use a larger anonymity set. If you use an anonymity set of 50, for example, then any link to "tainted" bitcoins is diluted beyond meaning.