It is hard to know the legitimacy of cloud mining operations. Any one of those cloud mining operations could potentially be selling (or have sold) shares of miners that do not exist, even if they have actual miners from bitmain. For example, they could have sold 120% of their actual mining capacity. It is also possible that bitdeer was shut down, but will continue to sell cloud mining contracts to minimize the losses to the owners of bitdeer.
Viabtc will fare the best, as they can sell the miners that were just shut down by the Chinese government.
Doesn't look like Bitdeer was shut down, their twitter account is quite busy the past few days.
"Minimizing the losses" to me appears to be restricted to blocking
Chinese IP addresses for now, at their own accord.
So they still have to see out their contracts, meanwhile ViaBTC bows out of all contracts but then only makes short-term income from selling their miners so the loss of potential revenue could be large if they do that instead of just repurposing them for their BTC mining pool.