Honestly I have been running these ads casino/gambling ads since long now
Google is best way to get traffic and you just cannot not ignore google then meta too.
other way is making sure you have two things in the media mix
a. back up agency or accounts so that even if your efforts are getting suspended you still not wasting days to get traffic.
b. try other platforms which has casino/gambling traffic it really depends on the country and what platforms allows to run such vertical for e.g. there are few push notification platforms which will work in asian countries or say some local OEM vendor will give you at par results like google search. you have to research them zero down few and try test or ask agency to do it for you
