Throwing out one idea: for the 30+ crowd with kids and families, how can you make it frictionless to maintain and build friendships, especially across different groups (building, schools, after schools, family)? Not necessarily as families, but just flagging events and making organizing events easier - my friends and I dont see each other nearly enough since we had kids. Everyone seems to be using WhatsApp for it and it's not great.

Friendster would be a great hit with the millennials. They had fond memories of that era and they’re done with the current social media trends. If you succeed with that niche, you might have a better chance.

You could probably make a decent niche business out of an ID verified, 30+ only social network. You'd need to find the killer use case though to get any kind of growth going.