Why is my Tecno phantom 9 keeps restarting

@papatee the Tecno Phantom 9 was launched in 2019. If yours still has the original battery, it is absolutely possible that this restarting is being caused by the failing battery. Replace the battery by using something like this video as your guide. Re-evaluate your phone after replacing it and let us know what happened.

While you work on your battery, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!