Here are a few options for a formal title, depending on your focus:
Most professional and standard:
“eYou Surpasses 75,000 Users Six Weeks Post-Launch; Extends Integration to Bluesky’s 44 Million-User Base”
Concise and authoritative:
“eYou Expands Platform Access to Bluesky Following Milestone of 75,000 Users”
Formal and strategic:
“eYou Reaches 75,000-User Milestone, Integrates with Bluesky’s Global Network Six Weeks After Launch”
Recommendation: The first option is the most formal and effectively captures both key developments in a clear, journalistic style.