lets say you have a site: mysite.com
you can make subdomains on that site such as: example.subdomain.com or supercool.mysite.com
adding subsomains is easy and free since if you own a a site all the subdomains under that site are your too. but subdomains dont fool IG crawlers into thinking its a diffrent site.
okay lets take this:
IG---->prelander---->website
this is what you need to do in order to avoid getting banned.
but you can buy 100 domains and have them link to your site like:
exaple.com and example.xyz will both lead instantly to example.com
But if you tried buying 100 domain names and have them all auto-redirect to your site like this"
IG---->website
you will get banned aswell