All-in-one business and professional ecosystem
Yes. There are platforms that cover some of these functions, but having all of them integrated into one platform is relatively uncommon.
PlatformBuy/SellLearnOpportunitiesForum/CommunityNews
LinkedInLimited
Facebook
XLimitedLimited
RedditLimitedLimited
UdemyLimited
Jumia
AlibabaLimitedLimited
AfriWallStreet
The opportunity for AfriWallStreet
What you're describing is essentially an all-in-one business and professional ecosystem:
Buy & Sell → Learn → Opportunities → Community/Forum → News
That is a strong positioning because a user could come to AfriWallStreet to:
  • 🛒 Buy & sell products and services
  • 🎓 Learn through courses and educational content
  • 💼 Find opportunities such as jobs, funding, events, partnerships and business opportunities
  • 💬 Join discussions and connect with professionals and entrepreneurs
  • 📰 Follow African business and professional news
  • 🤝 Network with businesses, startups, investors and professionals
The key distinction is that AfriWallStreet shouldn't try to be five unrelated websites under one name. The strongest strategy would be to make them connected parts of one ecosystem, with one account and profile across all sections.
A concise positioning could be:
AfriWallStreet — Africa's All-in-One Platform to Buy, Sell, Learn, Connect, Discover Opportunities and Stay Informed.

That could be a compelling differentiation from platforms that focus primarily on just one area.