Regarding Question number two: I replaced the original battery of my Galaxy s8 with an Ifixit s8 Battery and after around half a year, the batterylife began to decrease and now my nine months old battery performs quite bad. I only get around two hours of screen on time in energy saving mode.

I hope i could help you with That

Kind regards

I made this repair around nine months ago and for the first half Year the Ifixit Battery performed well. But after that time the battery drained very fast and i only get around 2 hours screen on time on energy saving mode. Right now the runtime is around the same as with the 3 years old original battery. Thats dissapointing because Ifixit is one of the only places you can buy good repair parts.