How to transfer google drive whatsapp backup to new iPhone?

Yesterday I lost my cell phone, luckily I ran my Sim card over the Whatsapp and can use the old number in my new phone. On my laptop, I saw that Whatsapp baked daily, so I'm wondering how to get the chats, etc. On my new iPhone?

Hi, is your backup now on Google Drive or Whatsapp that I can't read exactly from your question.

And for my understanding, you now have a new device with new software. Previously Android and now iPhone (iOS) correct?

How could you lose the mobile phone but keep the SIM card?