Rsync everything besides media to a Storj free account. I also rsync my most important data(docker compose files,config files, home assistant, a few small databases) to Google drive.

I have many of my services open to the internet, but behind authelia w/2fa and a reverse proxy. I haven’t had a security issue yet, been running this way for a few years.

I think it’s pretty safe as long as you keep them up to date. I run backups weekly and do updates at least once a month.

Using geoip restrictions will also help a lot because you can block most of the scanner bots by denying connections from outside your geographic region. These bots detect what services are open to the internet and then add them to databases like shodan. If a security flaw is found in one of those services, hackers will search those databases for servers with those services running and try to exploit them. If you aren’t in those databases they can’t easily find you before you are able to patch.

I think SSO is less important than having everything behind the reverse proxy. The importance of the proxy is that if there is a security hole in the web server component of your service, it cannot be exploited without a second flaw in the proxy. It’s an additional layer of abstraction and security that doesn’t add a ton of overhead.

An attacker would have to find an exploit in nginx, which is used by most of the big tech companies, so it is well secured compared to the services many of us selfhost.

Another advantage of using SWAG is being able to use fail2ban and geoip restrictions. Any ports open to the ipv4 internet get scanned by security services and malicious actors many times each day. It’s nice to be able to have nginx refuse connections from any of them that repeatedly fail to login, or that come from outside your geographic region.

If you’re going to try Authelia and a reverse proxy, I recommend using SWAG. It’s a docker container that includes Authelia, nginx, fail2ban, geoip restrictions, and has premade config files for most of the selfhosted software that people run. The config files are especially useful since they include comments that describe the settings you need to change within the services you run, like changing the external domain in Emby for example.

https://docs.linuxserver.io/images/docker-swag