The most secure is hire a real server (metal server) so you don't care the others thing. You are the only one person manage your server machine.
I checked some managed providers but if I buy extra managed service, its fee is very high. I would like to manage my VPS for myself, just a small issue is I don't know about how to secure it as good as others.
Nothing is secure if hackers can hack the government then they can surely hack a regular server. having said that a vps is usually safer than shared hosting. Because usually if a vps is compromised it's kept to that VPS container.
I don't think so, because more website owners know how to manage server hosting better than who is manging government's websites.