You're mixing software defined storage options with public cloud offerings, which is kind of strange. If you have your own hardware, Ceph is solid. I wouldn't

You're mixing software defined storage options with public cloud offerings, which is kind of strange. If you have your own hardware, Ceph is solid. I wouldn't put more than 200 million objects in a single bucket, but other than that it can be very reliable. I have ~ half an exabyte on-prem, and sleep very well at night.