Hi, my name is Neil, and I'm a Windows 10 user like you.
I'll be happy to answer your question.
Unfortunately the maximum battery report duration is set to 14 days.
If you try the following in Command Prompt:
powercfg /batteryreport /duration {days}
Delete the {days} and replace this with a number of days, like 7, you will get a battery report for the last 7 days. So like this:
powercfg /batteryreport /duration 7
If however, you try 365 (1 year), you will see that it says "Maximum duration is 14 days. Analyzing 14 days."
So 14 days is the maximum it allows I'm afraid.
There are some third party battery analyser apps out there. If you search online for "windows battery analyzer" you will find a choice of them.
I hope this answers your question.
Kindest regards,
Neil