Eventually I stopped proactively reviewing logs and stopped paying for the IDS. It was a waste of time and a distraction.
It's not hard to find really useful content that summarizes common vulnerabilities and attacks, and just use that to guide your server management. There are a ton of best practices guides for any common web server technology. Just executing these best practices to 100% will put you way ahead of almost all attackers.
And then the next best use of your time and resources is to prioritize the fastest possible patching cadence, since the vast majority of attacks target disclosed vulnerabilities.
Where logs are super helpful is in diagnosing problems after they happen. We used log analysis software to store and search logs and this was helpful 2-3 times to help find (and therefore address) the root cause of attacks that succeeded. (In every case it turned out to be a known vulnerability that we had been too slow to patch.)