[Q] phone shuts off before 0% topic

Hi, Is there any full proof method of fixing my phone battery so it shuts off at 0%?

My bacon shuts down at 8% - 4% usually.

and when it does shut down it blacks out. I don't get that pop up with a spinning circle saying you're phone is not shutting off.
Well, unless thats how the OPO shuts off by just immediately blacking out?

I checked to see if it was because my undervolt, so i brought back the voltages to stock, and unfortunately, the problem still remained.

I know you arent suppose to run these batteries dry, but it just irritates me that it would shut down at the 8% mark.
So any suggestions and fixes would be greatly appreciated!

Thanks