All RDS restores create a new instance.
On top of that if you want to do a point in time recovery within your designated recovery window, you MUST use an automated backup.
PITR uses log files to recover to a specific point in time within your recovery window by using log files that are saved every 5 minutes with RDS automatic backups turned on. Therefore you RPO – recovery point objective – will be at up to 5 minutes of data loss.
Desired RPO expresses the amount of data loss expressed in time that is tolerable. Since RDS logs are backed up at most every 5 minutes, your maximum RPO is 5 minutes. I do not believe you can change the log file backup frequency with RDS.