If the cloud mining site is a Ponzi they could care less about the halving, will stay afloat as long as new investors send funds allowing them to make payouts.
I agree with you. There's only one site that I think is legit (maybe more legit mining sites out there) and that is HashNest. HashOcean um um um.
We can't be sure on the cloud mining sites out there because even the "most" trusted and on the top 1 of the reviews or rating about cloud mining sites gone wrong and just to turned to scam and that is hashocean. It's better to spend your bitcoin on other ways like trading or other ways that you are the one who will take control of and you will feel more comfortable than investing.