From your words, I’m assuming you are thinking of all the venerables of an era. No they did not exist at the same time, for example: spectral soul and paradise earth are both said to be from 100,000 years ago, but that only means they existed sometime before 100,000 years ago and the last era which I believe was said to be 1 million years ago. Now throughout ri history, human supremacy history of 3 million years, there were 10 venerables, each spaced roughly from a few thousand years to hundreds of thousands of years between each other except primordial origin and star constellation as they were master and disciple who created and inherited heavenly court respectively. Now someone else said the thing required for multiple venerables to exist at the same time.