Fast Cultivation vs Slow Cultivation

I'm an aspiring writer and I want to write a novel with that cultivation element. But the cultivation speed makes me scratch my head and I can't make up my mind. I'll put the points I think:

Observation:

Rapid cultivation = End of cultivation after 30-50 years.

Slow cultivation = End of cultivation after 10,000 to 100,000,000 years for example.

Points for each:

Fast cultivation

  • I feel like you can enjoy the weaker/familiar characters because not much time has passed.
  • Enables greater rhythm control.
  • Less realistic
  • In need of more plot armor in my view.

Slow cultivation

  • More realistic
  • Emphasizes the MC's effort
  • Long passages of time can be bad for the reader and the author.

I would like you to give me your opinion, please.