Stick to 10-15 per hour, no more than 150 a day. And 7500 is the total limit of follows you can have on your IG account.
Keep it as random as possible, if you do precisely 15 an hour and do it quick one follow after the other, it’s easy to detect. The main idea is to behave as randomly and human like as possible, but you already know that.
Content is king. Good content is all you really need to perform good on Instagram, and the rest will come.
While the algorithm is complicated, it really boils down to posting good content that makes users want to engage, if the content is good, and people engage, the post will be recommended more and more… and in return your account will grow.