Aws backup : How to forced a full backup

Once a full backup is obtained, subsequent backups are incremental.
So if we were to do it, we would delete the full backup each time and then get a backup, which would be a full backup.
https://docs.aws.amazon.com/aws-backup/latest/devguide/whatisbackup.html#features-by-resource

As described in the following document, even if a full backup is lost, the data can be fully restored from the incremental backups taken afterward, so there is no point in taking a full backup every time.
https://docs.aws.amazon.com/aws-backup/latest/devguide/creating-a-backup.html#how-incremental-backup-works

Depending on the type of service, you can enforce a full backup. If it is EFS, S3, VMWareVM's or DynamoDB with advance feature enabled then you can create a full backup by creating an on-demand backup to a vault where a previous backup for the same resource doesn't exist. Basically, you have to pick a different vault.

For EC2, RDS, EBS, etc, the backups are region wise incremental. That means all the backups for these resources are incremental in the same region.