The is why I'm glad I use a Linux distro with 100% HDD / SSD isolation.
Don't forget PC firmware. Sadly all the UEFI/tpm bugaboo has not resulted in PC firmware being protected by default, or even having sufficient options (PBA, spi lock) to secure automated flashing. Ironically, a tool like fwupd will even mark a write-protected firmware as vulnerable. That aside, a distro like easyos will not feature the daemon by default, which is a bonus.
This sort of stuff isn't too hard to do. It can be mostly automated.
The automation got much better, as did the availability of up-to-date cloud based Linux templates for virtual hosts. Still, I'd still call it too advanced for the average Linux user who sets about to use a cloud VPS or something.
For example, fail2ban runs as root and has also been exploited in the past (e.g. CVE-2023-30258, scale 9.8). Being knowledgeable enough to deploy it safely (e.g. on a cloud host, automatically setting up IP sets of malicious actors) IMHO automatically makes you an advanced admin. Also, if you run something like a public ssh-server only, it
will be probed
all the time regardless. It will likely be more resource efficient to let the system's kernel automatically limit connection attempts (e.g. ufw limit ssh/tcp). There is no golden recipe, most certainly you'd have to get into the details depending on use-case of the system.
the ultimate safety valve for them is that they can be discarded and an identical clean new version run in the face of any issues.
I agree. Probably the most overlooked topic in this regard, being able to keep data safe and redeploy in a fresh instance. Aside from discussed malware, more automation mean more points to break. How much data can you afford to loose and how much downtime is tolerable, are questions to ask.