@Murat Cetink, we initially launched on an EC2 for production but ran into some resource issues after a bit. However, we're using to sync a large volume of connectors (50+ connections) with heavy amounts of data (we're an agency) so we had to migrate to K8. However, when we were running it with just 5 to 10 connections, the EC2 worked just fine.
One suggestion I'd make is migrating to a standalone Postgres server sooner rather than later. It is helpful to have easier access than having to connect the docker container and it allows for backups.