Instagram help centre says that you can have up to 5 accounts. You can also switch between them without logging out. If you want to switch the accounts, you need to tap your username at the top of the screen and then tap the account you’d like to go to.
What happens after 10k followers on Instagram?
Once you have 10k followers, Instagram will make it easier for you to get people to your website via Stories with the swipe up to link feature. Swipe up is the only way to get a direct link from your Instagram to your other web properties. And, it’s available in STORIES, if you have 10k followers.