What are the prevailing fan theories about the true ending of the Invincible comic series?

Fan theories often revolve around the potential survival of characters presumed dead, alternative outcomes for key plot points, or reinterpretations of the final panels. Many discussions delve into whether Mark Grayson truly found peace or if lingering threats remained. Some theories propose that the Viltrumite threat wasn't fully eradicated or that other cosmic entities could emerge. Others focus on character relationships and speculate on long-term dynamics not explicitly shown in the final pages.