I am not able to update whatsapp due to download with different account

I don't know how Whatsapp works. You should ask this on a forum for WhatsApp. Some apps store data specific to an Apple ID, so if you download with a different ID you lose all the data. Others store data on the app's site and if you log in with them it should reappear.

You can't. If the chats are backed up to a different iCloud account, you cannot get them back.

It should still show some recent chats though when you set it up.

For further help, contact Facebook / Meta as Whatsapp belongs to them.

click here ➜ https://faq.whatsapp.com/209942271778103/?cms_platform=iphone