Non follower insights

My insights indicate that non follower account/s regularly view my highlights after the 48 hour window for seeing who has viewed it. Typically they view all of the posts on the most recently updated highlight. This has been going on for some months now and I’m curious as to who is doing it and why they are doing it.

Is this likely to be 1. bot activity, 2. Random people who click on my profile and view all of my highlights (seems highly unlikely) or 3. stalking?

Additionally, are there any methods which I can find out/ catch the account/s which have been viewing the highlights?

I’d appreciate any and all help, as this is kind of bugging me. Thanks.