Is there any logical way that a "cloud Bitcoin mining" operation could be anything but a scam?
If you found yourself in a situation where you owned a machine which, when running, would create a profit for you, what would you do?

run that machine
set up a business to rent the profits of running that machine to others

The only way the second choice really makes sense, is if you rent it out for more money than you'd expect the machine to make for you on it's own.

Wouldn't it make sense for them to use my amount to buy another miner (or part of one) and then I would regularly get &quot;my share worth&quot; of satoshis?

Mining is very competitive. As a miner you have to minimize your costs to remain profitable, and so I find it hard to believe that any miner which is depending on renting out their hashrate to others will be competitive. There would be a lot of extra work involved in running such an additional operation. Maybe it is possible, but personally I wouldn't bet on it.
If you search around online, you'll find lots of stories of users that have lost money on cloud mining purchases, but are there many that talk about big profits? Not that I've seen at least. That isn't a perfect measure, but it is perhaps telling.