[Task] Query Optimizations

[happydracula]

Description

Few repository methods can be optimized

Use Case

Fetch Related data using a JOIN query rather than issuing multiple SELECT's effectively avoiding the N+1 query problem

Suggested Solution

1. Optimise queries - Instead of fetching related rows separately-we should be fetching them using a single JOIN query. Refer to this: Added onboarding endpoints #27 (comment), Added onboarding endpoints #27 (comment)

---