Is it possible to copy all session/login data of WhatsApp web from one browser to another so that I can use WhatsApp web on another browser without the need to scan QR code again? ,
Whatsapp has not provided such a feature yet, But you can use whatsapp web on the same browser again again till it's id is kept save in your whatsapp app. You have to scan QR code atleat once to access this feature. Later it may possible to launch OTP or other methods to access whatsapp web.