If you are able to start it up, go to Settings > Battery > Battery Health & Charging > Maximum Capacity, and make sure it is over 80%.
The analytic logs are going to be unhelpful for a self diagnosis/repair. They may be used by an Apple Engineer that has specialized decoding software to resolve issues that have been opened with a Support Ticket, but only if they are requested. Take your phone to an Apple Store for diagnostics or it may even be possible to get online diagnostics.
Genius Bar Reservation and Apple Support Options - Apple
If the issue is not due to a failed battery, don't be surprised if it requires a Logic Board replacement for any hardware issue. Costs and details of any needed repair would be provided by Apple. The first thing they may try is a software restore.