iCloud and WhatsApp

I downloaded the WhatsApp app on my new iPhone but connected as a linked device without paying attention and deleted the WhatsApp app on my old iPhone. I didn’t have the backup option in my WhatsApp settings so I switched to WhatsApp business. I barely got my last few contacts I chatted with. But I saw that the last backup on iCloud was few months ago. I mistakenly backed up again and now it only backed up those few pending chat history I had. I redownloaded the app again and it only restored the few things. I need the old Backup with the old chat history. please How can I get it?