What is the best way to protect a gamer VPS on Linux?

I have a main dedicated server that I divided into 5 VPSs, for my 5 individual game servers. Every time I need to perform maintenance or update any server, I have to open my notepad and check the password for that VPS. The problem is that I find this a huge waste of time.

I’ve been researching some tutorials on the internet and saw that you can configure it to be passwordless, by creating an SSH key that stays on your PC. And to make it even more secure, you can disable password login and allow only SSH access.

I saw that it’s easy to do. The only doubt I have is whether this is really secure? Is there no way to force something, I don’t know? I’ve even set it up on one of my VPSs to test. When creating the SSH, it asks if I want to put a password on the SSH. I found this to be a pretty cool feature because it’s like having two-factor security.

What do you guys think?

I was also thinking about creating a CNAME for the machine’s IP, to connect like this: mygametypemyvps.mydomain.tld. Would it be wise to do this or would I be exposing my IP in some way? I’m using Cloudflare with proxy.