First and the main one is the affiliate/referal programas, this way by sharing your affiliate link you will get some incom from the users bets, isn't easy to get good affiliate (users who bet a lot) but with one high roller you could make a descent amount.
I thought the title was clickbait but this really fit well to the description. However, this is only profitable when you have a lot of follower like influencers since it’s very hard to attract affiliate these days by just spreading your affiliate link.
The second one is the VIP programas, like the one that stake offers, you need to bet to grow your account, but once you have a good VIP level you will get a weekly and monthly prizes, It will be better if you bet that month but even without betting you will get something each week/month.
This one seems not possible to happened without losing big in the process. Stake needs huge wager volume in able to achieved higher VIP level. It means you might suffer huge loss first in able to achieved that.