People are missing the point dramatically... yes you have a public profile and anyone can look but-
Someone has gone to a lot of effort to either make a fake profile or use a fake profile and view your stories consistently, if they don't follow you they have to type in your name (or go to their search bar and depending on who else they've been looking at you may still be on the list or at the top).
I would guarantee it is someone you know or that knows you, not a "bot".
I had a similar thing happen to me, the fake account used a profile picture of a fairly big influencer and followed 17 people... looked at my stories consistently.
Also began to message my bf at the times page with messages such as "you're cute" etc etc. which he never responded to but it was clearly fishing for a response from him to possibly send me (not 100% sure).
We did the "forgot password" trick as above and turned out it was a girl he went to school with and had matched with briefly on a dating app before we met. They spoke for about 3 weeks but never met for a date or anything... I think she was just miffed when she saw he had a gf and took an unhealthy interest in me. The lady 3 digits of the phone number matched hers in his phone and the email address was not only had her initials in but also was a company email address for where she worked.
And before anyone says he was having an affair with her etc. he showed me the messages between them which was chit chat and brief flirting over a few weeks. She asked him out for coffee and he said he was busy that day. She then asked what he was looking for and he'd said he wasn't sure if he was in the place for a relationship right now and was just looking to have fun and see how things go with someone... I'm not certain but she may have got funny about him saying he didn't want a relationship and then her seeing he was in one a few months later...
We were all mid 20s at this point btw- it was all very odd and not something I would ever do but people do act strangely OP!
It's the brazen people that get me- I had an ex from years ago new gf looking at me religiously as well on her own account, I haven't had anything to do with him in a long time and only found out as I had a mutual friend with her and asked them. This went on for months and months! I would never as I'd be worried the other person would see!
Sorry for the long reply OP but I'm hoping it helps as I feel you are looking for an answer- I would absolutely guarantee you in my experience that it is someone how knows your or your partner, an ex, something like that. It's the only reasonable explanation.
People do some odd sh*t.