How to share RDS snapshots across account roles?
To my knowledge there are only Tag based Iam policies available to limit access to resources for certain users or user groups.

Because of this, you should simply be able to tag an RDS snapshot both production and development for you to access it with your development user or group.

There are a large number of security considerations to think through, so don't undermine the security setup. I would therefore expect that only manual tagging is appropriate for this specific use case