Aiven is great if you don't need the superuser access. They will run some bigger plans on local SSDs and allow you to create replicas and migrate across clouds and regions easily. It's a great way to run multi-cloud without shipping the data yourself. True that they could use more alerting features on resource usage.
GCP managed services of open products are highly unrecommended for this exact reason of being very behind or even obsolete with very limited customization and control. Stick with BigTable, BigQuery, Dataflow and run the rest yourselfs on GCE/GKE.