No. According to Jain Dharma, all humans do not die at the end of the 5th āra.

A few key points from Jain time‑cycle (kāl–chakr) doctrine:

1. Time is cyclical and eternal

- There is no total “end of the world” or complete destruction of all beings. - One half‑cycle (Avasarpiṇī – descending) smoothly turns into the next half‑cycle (Utsarpiṇī – ascending). ( jainknowledge.com)

1. What happens in the 5th āra (Duḥṣamā / Dukhmā)

- It is an age of increasing sorrow and spiritual decline. - No new Tīrthaṅkars or Kevalīs arise in our Bhārat Kṣetra in this period. - Liberation from here is not possible in this āra, though souls continue to take birth and die as usual. ( jainknowledge.com)

1. What happens at the end of the 5th āra

- The 5th āra simply changes into the 6th āra (Duḥṣama‑duḥṣamā), which is even more miserable. - Humans are still born, live, and die in the 6th āra, though with very short lifespans and almost no religion. ( jainknowledge.com) - There is no teaching that all humans are wiped out at the boundary between 5th and 6th āra.

1. Long‑term view

- After the 6th āra ends, the Utsarpiṇī half‑cycle begins, and conditions slowly improve again; new Tīrthaṅkars will come in that ascending half. ( jainknowledge.com)

So, Jain cosmology does not describe a “mass extinction” of all humans at the end of the 5th āra. Instead, it describes a gradual worsening into the 6th āra, then gradual improvement in the next half‑cycle.

You can read a simple explanation of the Jain time‑cycle and the 5th āra here: