I don't disagree, I feel like we might be using it wrong. We were trying to replace ES with it but it just doesn't feel like it fits our needed usecase.
You don’t need a cluster nor should you be having any issues you mentioned. I run 10x that volume daily on a single gcp box (8 core / 64GB). We migrated off BigQuery and went from $10k/mo to about $250/mo. And it’s faster for both low-latency and big slow queries.