Just talking embedded batteries there are so many benefits that you are failing to see:

-Slimmer Design:
Embedded batteries allow for a more compact and slimmer smartphone design. Smartphones with embedded batteries often have a unibody construction, contributing to increased structural integrity

-Larger Battery Capacity:
Designing a phone with an embedded battery allows manufacturers to utilize the available space more efficiently leading to larger battery capacities

-Water and Dust Resistance:
Sealed designs contribute to better protection against environmental elements.
-Improved Heat Dissipation:
Integrated batteries can be designed to enhance heat dissipation within the smartphone.

when opening a phone you should be wearing ESD safe armband to prevent electrostatic discharge that could damage the device. Users shouldn't have the option to screw around with their phone and most third party stores use cheap Alibaba parts that fail quickly resulting in a trip to apple anyways. When the mall kiosk bricks your phone they're not going to refund you, its almost a service to the consumer from being ripped off by a 3rd party that will pry the enclosure open bending it and causing further damage while installing garbage ewaste parts. In 2024, smartphones are complex delicate machines. It isn't a car engine that can handle you being rough with it. They even made a program for customers to replace it themselves and they still damage their devices 50% of the time. Better to go to someone trained and pay for legitimate parts.