Addressing Persistent N+1 Query Issues in Eloquent with Complex Relationships for Laravel Performance Optimization

Following up on our discussion about optimizing Laravel for high-traffic applications, I'm facing a particularly stubborn challenge with N+1 query issues that are severely impacting response time.

• Context: We've successfully tackled many general performance bottlenecks, but deeply nested Eloquent relationships and polymorphic associations are still generating an excessive number of queries.
• Specific Problem: Even with common eager loading techniques, certain pages with complex data structures involving several levels of related models and conditional polymorphic loads are still exhibiting N+1 patterns, leading to unacceptable page load times. The issue isn't with simple hasMany or belongsTo, but rather when combining multiple with() calls on deeply nested optional relationships, or when polymorphic relations are involved in a large collection. This significantly hampers overall Eloquent performance.
• Attempts Made: We've extensively used with(), load(), withCount(), and even some manual joins/subqueries where feasible. Laravel Debugbar and Telescope have helped identify the N+1s, but a robust, scalable solution for these intricate scenarios remains elusive. Merging collections or using custom SQL where Eloquent becomes too cumbersome has also been considered but feels like a workaround rather than a systemic fix.
• Seeking Advice On: I'm looking for advanced strategies for query optimization in these specific complex Eloquent scenarios. Are there best practices for custom relationship loaders, more efficient ways to handle conditional polymorphic eager loading, or perhaps specific packages/patterns for optimizing database interactions when dealing with highly interconnected data models? Any insights on database-level optimizations or index strategies that specifically alleviate these complex N+1 patterns would also be invaluable.

Thanks in advance for your expertise!