Only buying from AWS/GCP doesn’t get you security. Reliability, may be. Running a secure cloud server is pretty much a job like. You have to have a lot of knowledge about security in the first place and then ensure you have configured everything correctly and haven’t left any loophole that got exploited. It is also not one time work as you have to keep updating your OS and your softwares regularly to avoid having any vulnerability unpatched.
Now a days, with so many cyber crimes happening, once they figure out non techy folks are setting up cloud servers and running algo in it, they would be all over it. Once a VM is compromised, they get your broker keys and tokens and totps and passwords and what not. They wont even withdraw your money to their account. They can easily place some orders from your broker account into a pump and dump stock and take all your money in the most legally illegal money transfer known to man kind. No way to trace this money transfer. Forget getting it back.