Having 2 accounts (5 max.) with the same email is allowed by Instagram. You won't be blocked and each account will work normally. They're differentiated by a unique username.
If you comment, like, follow or unfollow in a short period of time, Instagram may block your account temporarily from performing these actions to prevent abuse. In addition, comments deemed inappropriate (according to the Community Standards) are removed.
Try spacing out your comments and other interactions (likes, following, ...) to prevent your account from being flagged. Don't include more than 5 mentions and 30 hashtags in a single comment. You can't also post the same comment multiple times, even emojis.
If Instagram hasn't restricted your account, users are also able to block you from commenting on their posts. This can be completely or until they approve your comments. The above recommendations don't apply in this case, as it depends on the user's choices.
Hope this helps.
Instagram may remove comments they deem inappropriate according to their Community Standards. If you make too many comments, likes, follows, or unfollows in a short period of time, Instagram may temporarily block your account from performing these actions to prevent abuse.
- Avoid unfollowing or following more than 50 people at a time.
- Do not spam comments on someone's post.
- Do not use Automation Softwares.
- Follow Instagrams Community Guidelines Policy while using the platform.