@Decyb Your mobile phone contains info which uniquely identifies it. When you create multiple IG accounts, you need to ensure you're not sending all of your phone's details. Otherwise the a holes at FB will give you a kick in the nutsack.
There are some posts on the forum that explain how to do it.
Essentially it involves rooting your Android device or installing BlueStacks (Android for your desktop) and changing device data (MAC, ID etc) as well as changing IP address when creating new accounts.
The reason I go to the library is that hundreds (possibly even thousands) of people login, create, and use FB/Instagram there all day (using free wifi). So if some fat prick like me comes in with a bag of donuts, an old Android phone and 20 SIM cards, no one - not even suckerberg - bats an eyelid.
I know there are faster ways to do things (various automated account creation tools) and you can purchase premade accounts... but many of the accounts you buy are just asking for problems. They've often got names like "Bob123 Jones" or "Amit365 Habib" and have 4,896 global "friends"...
If you start posting in groups with accounts like this, there's every chance (even if your page/s) were previously in good standing, you're going to attract some unwanted attention.
If you take the time, make the accounts seem real, and don't go crazy from the outset, it's possible for them to be an asset capable of growing your business long term. I'm not interested in CPA... I'm interested in growing brands, driving traffic and generating sales.