Installing an operating system and enabling encryption won’t overwrite the data on the entire disk. Instead, it will only overwrite on the specific sectors on which this operating system was installed.

Other “previous” data on the disk will remain intact and unaffected.

No.

My privacy hardening tips are:

• Avoid 5-eyes, 9-eyes and 14-eyes countries^[1].
• Don’t use CloudFlare or any CDN/AntiDDOS services because they decrypt all traffic that goes to and from your server^[2]^. You don’t know what they do with it.
• DNS queries sent by the server should be encrypted^[3] so that the ISP/data center cannot see them.
• If you want a VPS: try getting KVM instead of LXC one. It’s so easy to automate processes scanning on the fly^[4]