What I'm seeing matches the observations of the other commenters here exactly: most of the "users" are bots harvesting pages and PDFs. My solution for getting at the real users is GoatCounter.
Again, if I remember correctly, it was able to make reports for AWS Cloudfront logs, which was actually useful.
For ad hoc analytics these tools are very nice, but for long-term stats they run into timeouts, because the backend needs a lot of time to collect the data and build the reports for ~1 month or a quarter — or am I wrong about that?