Hi @gaetan_welow ,
The best approach to do a Replica database with Qovery is to use Lifecycle Jobs.
You can check this AWS RDS database deployed via Terraform and a Qovery Lifecycle Job.
You can also check out this complete guide
To give more context, we provided the Lifecycle Job as a customizable way to spin up any resources. So, spinning up an AWS RDS instance with a replica via the lifecycle job is possible, and you can set up your replica the way you want.
I really invite you to read the guide I provided above; it explains everything. You must provide your Terraform/Cloudformation/Pulumi/Whatever configuration to create your Replica.