Let me know if you need any help with that. I'm still a beginner, but have used the last few months to learn about cyber security. It can be a daunting subject, but if you get the basics right, you're probably good. I also hosted without a care for years and was never hacked, but it can/will happen. Here are some pointers!

Get or use a firewall. Iptables, UFW and such are probably good enough. I myself use OPNsense. It can be integrated with Crowdsec, a popular intrusion prevention system. This can be quite a rabbit whole. In the end, you should be able to control who goes where in your network.

Restrict ssh access or don't allow it at all via internet. Close port 22 and use a VPN, if needed. Don't allow root access via Ssh, use sudo. Use keys and passphrase login for best security.

Update your stuff regularly. Weekly or bi-weekly, if you can.

Use two factor authentication, where possible. It can be a bit annoying, but improves things dramatically. Long passwords help to, I use random-word-other-word combinations.

If you haven't, think of a backup strategy. 3 redundant copys on 2 media, one off site.