It is not recommended to do email blasting on Gmail. Instead, we would advise using Groups or distribution list in G Suite for mass mailing.
Business Edition has not restriction to group based mailing. The limit per day is 200 emails per accout. All editions are restricted to 500 users per email.
Please visit the following for more details
ttps://support.google.com/a/answer/167085?hl=en
https://support.google.com/a/answer/166852?hl=en