You can import your Whatsapp chats into telegram without asking Whatsapp for your data, or using any 3rd party apps.
The annoying thing thoug, absolutely on whatsapp side, is that I have to export chats one by one.
Shouldn't I be enabled to extract my own backups, on my own gdrive, to read my own chats ?
Spent way too long diving into that rabbit hole one time when I switched phones, activated WhatsApp without thinking about it on the new phone (and didn't restore, or switched back and forth, or something) and refused to go on with a history split between two devices. Eventually managed to merge the databases, put it on the new phone, and reinstall (since you can only restore during first-time startup...). Absolutely not worth the time it took, but I was stubborn.
I'm not saying that isn't shit, or that WA expects you to do that, just that if you want to, it can be done.
this is news to me - i will definitely be using/chasing this lead to get my data, thank you!