PITR testing for disaster recovery

According to this: https://repost.aws/knowledge-center/dynamodb-restore-taking-long

The time DynamoDB takes to restore a table varies based on multiple factors and is not necessarily correlated directly to the size of the table.

so a simple proportion may be misleading and it is very hard to do.

If you really need this estimation, and you are allowed to, an approach could be to duplicate masked data from production to dev and perform PITR.

The golden rule is to never test in prod, however, testing your RPO and RTO for the system is important. If you do not have the same data in a lower environment, then I would test it in prod, PITR does not impact production tables in any way.