I don’t think there exists a proper alternative even in the commercial sector.

There is a handful of vendors and they indeed monitor a ton more than just viruses. The solution we're running at the office monitors pretty much all kinds of logs (dns, dhcp, authentication, network traffic....) and it can lock down clients which are behaving wrongly enough. For example every time I change a hosts file (for a legitimate reason) on my own laptop I get a question from security team if that was intented. And it combines logs/data gathered from different systems to identify potential threats and problematic hosts and that's why our fleet feeds in data from all kinds of devices.

I haven't seen that many different solutions which do this, but the few I've worked with are a bit hit or miss with linux. The current solution has a funny feature where it breaks dpkg if the server doesn't have certain things installed (which are not depencies on the packet itself). And they eat up a pretty decent chunk of CPU-cycles and RAM while running. But apparently someone has done the math and decided that it's worth the additional capacity, it's outside my pay range so I just install whatever I'm told to.