Unable to connect to MySql DB AWS RDS - MAC

Hello.
Are you trying to connect to RDS directly from your local machine (Mac OS)?
In that case, you need to make sure that the required IP address and port are allowed in the security group configured for RDS.
In addition, RDS Public access must be enabled when connecting directly from the local machine.
https://repost.aws/knowledge-center/rds-connectivity-instance-subnet-vpc

When connecting from EC2 to RDS, it is necessary to confirm that the EC2 IP address or security group is allowed at the source in the RDS security group.