What are the best practices for designing an engaging and user-friendly social media feed?

I'm working on a social media app and want to create a feed that keeps users engaged without overwhelming them. What design principles or features have you found effective for making feeds both intuitive and addictive?

How do you balance content variety and relevance?
Do you use algorithms or manual curation?
How do you handle ads or sponsored content without disrupting the experience?
Any UI/UX tips or examples that worked well?

Would love to hear your insights!