iPhone 5s battery draining quickly but apparently still has most of its capacity available according to iBackUpbot and Battery Life

I have had my iPhone 5s for a few years now with no issues but recently been having serious issues with my battery. It is draining multiple times a day and as such it almost constantly needs to be plugged into either the outlet or a powerbank. I thought that it was strange that it was sudden and wanted to see if perhaps I needed a new battery by looking at the capacity but can find no problems there. I have attached screenshots from both applications in order to get more detailed help. Screenshots

I have also restored my phone back the standard ios and have seen no improvement.

Is there anything I can do to be sure that the battery is dead?