understanding the instagram algorithm?

instagram sometimes bans the accounts randomly. for example, you are running fine with your instagram accs + bot for almost 2 months and suddenly some of your accounts got banned, but others are still alive. does it mean instagram sometimes does manual review? maybe an employee saw your acc looks fishy so they click the ban hammer.

what do you think? what is the actual reason of ban, (sometiems because of the setting,sometimes because of the proxy, and sometimes it's just ban without a reason / random ban) how to understand the algorithm and how to bypass it for a long-term (maybe botting for a year or so)

The ban hammer doesn't come without reason and it is not "random" as you put it. Because one of your botted account is alive and the other isn't doesn't necessarily mean its random. There are thousands of accounts created every day and millions in existence. If you are botting or doing something you shouldn't be doing, when you get banned it isn't a coincidence it is just they have finally caught you doing it. In the end everybody has their "opinion" as to what will keep you under the radar, but it is very rare an account gets banned for no reason at all.

Also, your title is a bit misleading, normally when a person speaks of an instagram algorithm it is about engagement/likes and feed. Not backend botting stuff.

When people report you, it can be manually reviewed. From there it is very easy for them to find out your botting

Most bans start with somebody reporting you