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.
i would emphasize that you cannot lump coinbase together with all exchanges. many exchanges will do no such thing.
specifically, binance.com and kucoin (unless things have changed
very recently) do not have any terms prohibiting gambling. you can freely send them coins from gambling sites---i have---and withdraw "clean" coins from their hot wallet.
it's probably sensible to do a few nominal trades so it doesn't look like you're just using them to pass funds through.
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.
it may not be taint that gets you, but simple association with wasabi wallet coinjoins. multiple exchanges have acted adversely against customers who deposited/withdrew such funds.
i would much rather own clean outputs withdrawn from an exchange than coinjoin-linked outputs---at least until bitcoin privacy is improved enough to obfuscate coinjoins. sadly, that is the price of fungibility.