I am trying to back up my 8G WhatsApp chat history to my iCloud+ (50G) from my old iPhone 6 (16G) and restore it on my new iPhone 13 (500G) but it doesn't go through!

I am aware of the following rule by WhatsApp: "There must be enough free space on both your iCloud and iPhone. You need to have at least 2.05 times the space available in your iCloud account and on your phone than the actual size of your backup."

On my old iPhone 6 (16G), I have WhatsApp (8G), iOS 12.5.4 (6G), and free space (2G), so I can't delete anything to make more space for the backup process! I was wondering if there is a way around this. For example, can I export each of my individual chat history as a zip file to my iCloud and restore it one at a time? or export my WhatsApp chats to Telegram and can have access to WhatsApp chat history on my new iPhone 13 (500G)? I feel stuck here! please assist me with this matter.