Yeah I am surprised there are not more casinos which support the lightning network.
The Lightning Network (LN) was already introduced before and until now I can't see significant progress. In my opinion, I think even if casinos support the LN it would still depend on the gamblers themselves. I mean, as a gambler, personally, I don't want to approach gambling in a complicated way, and I think LN is just complicated for some as they can just easily use altcoins in order to save on fees and transactions are also almost instant for some altcoins.
But I can't blame OP, everyone has their own choice and I think the users above had already suggested some reputable casinos that supports LN.