The Eternal Buddha and Vairocana vs. Purusha?

[Individual]

Don't like to ask scholarly questions with no purpose... But I'd really like to know:

How is the eternal Buddha (of the Lotus Sutra) and\or Vairocana Buddha distinguished from the "Purusha" (Cosmic Man) of Hinduism?

[ground]

Just speculating since I am not sure about the view the Lotus sutra is based on:
Through the mode of asserted existence.

I am saying this from the perspective of Madhyamaka. But there may be others who disagree.

Kind regards