Design an concurrent History tracking system where we can store and track history of registered entities. We should be able to onboard service and their entities to our system and start tracking changes being made to them

Functional requirements (FR)

Ingest or maintain the source data required for the requested search, ranking, analytics, or alert behavior.
Let authorized users query results using the filters, time ranges, or preferences in scope.
Refresh derived results as source data changes and expose freshness or confidence where relevant.
Provide controls for subscriptions, thresholds, or saved views where requested.

Set measurable freshness, query-latency, and throughput objectives.
Define correctness bounds for aggregation, ranking, deduplication, and late-arriving data.
Protect user and event data and enforce tenant access boundaries.
Make data lag, query failures, alert delivery, and cost visible to operators.

Define the scale, success measures, and operational ownership before committing to an architecture.
Compare at least two viable approaches and explain the trade-offs, migration path, and failure behavior.
Identify the riskiest assumptions and how you would validate them with data or a staged rollout.