It's a bit like finding a single thread and unravelling it.
I used to get dozens of these things banned a day, there were a lot of us bot hunters reporting bots.
They sometimes sound "off", stop in mid sentence, reply to people as if they think it's the OP, reply as if they are OP, or post 💯 by itself. Or they have a username that fits a recent bot pattern (e.g. appending "rp" to existing usernames)
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If you see one slip up once, then looking at its other comments will often lead you to new bots simply because they are all attracted to the same positions (prominent but a few comments deep).
Certain subs like AITA and r/memes are more prone to them so I would go there for easy leads.
Also if you check its actual submissions, a karma laden bot will often repost hobby content, then have a second bot come and claim to have bought a t shirt or mug with that content and post a malicious link. Then a third bot will pose as another redditor saying thanks I just ordered one to the second bot. Following those bots leads you to even more bots, etc.
Aurora_Borealia