I used this software.

https://www.tenorshare.com/whatsapp-transfer-backup-restore.html

I paid for the 1month license. The entire transfer process took almost 8 hours. and during the entire duration, i was nervous that i might end up bricking up a brand new Iphone 12 pro max. But i got all my messages.

2 years back, i transferred from Pixel 3XL to Iphone. i transferred almost 15GB whatsapp messages (doest not include images, docs or videos), chat history dating more than 8 years.