It depends what you want to do with it. If it’s just for storing files/backups then encrypt them before uploading and make sure the key never goes anywhere near the VPS. If it’s for serving up something like a simple website, you probably care more about data integrity than exfiltration, so make sure you have the security, including selinux or equivalent, locked down, and regularly run integrity checks. If it’s for running something interactive, or where data will be generated or downloaded to the machine, you’re out of luck, there’s no even theoretical way of securing that against an adversary with that much access.
I enjoy reading dead tree books as much as anyone, and whilest the publisher/distributor can’t take it away, there are plenty of ways you can lose access to them. Fire and flood being the two obvious ones, whereas digital books can be backed up offsite. It’s also easier to carry many books when they’re digital compared to physical.
For books I care about I try to get both a physical and a (drm free) digital copy for the best of both world.