Nokia 6.3 (could also be named Nokia 6.4) and Nokia 7.3 (could also be named Nokia 7.4) smartphone models may be in the pipeline. They will reportedly come with 4,500mAh and 5,000mAh batteries, respectively. The models were spotted on TUV Rheinland certification website.

source https://gadgets.ndtv.com/mobiles/news/nokia-6-3-6-4-7-3-7-4-4500mah-5000mah-battery-capacity-tuv-rheinland-certification-2344976#rss-gadgets-all