The Communist Manifesto was a pamphlet written within the context of Marx's time, and the Material Conditions that came with them. They were not meant to be the solution, but a solution, and for his time period.

Reading the Communist Manifesto as a means to say Marx's ideas are problematic by stripping them from their context and slapping them onto modern times is a disservice to Marxism.

Marxism is a frame of analysis, a philosophical method via Dialectical Materialism, and a tool for looking at how to improve whatever situation you are in. As such, further reading of Marx beyond the Manifesto is a requirement to understand what Marxists of today advocate for.