Instagram does not let you fully hide your followers list from everyone
Make your account private to limit who can see your followers
Remove followers you do not want to see your profile
Block specific users to prevent them from viewing your account and followers
Restrict users if you want to limit their access without blocking
Avoid accepting follow requests from people you do not want to see your followers
Hide your activity by turning off Activity Status
Review third-party apps and revoke any suspicious access to your account