The Samsung Galaxy S21 has a fairly high repairability score of 7.75 out of 10. The back plate is easily removable and most of the parts are replaceable. However the battery is difficult to remove due to the strong adhesive underneath and the lack of pull tabs. Overall the device is fairly repairable and should not pose too much of a challenge for experienced technicians.
Disassembly
Positive
Negative
Battery cable and the Battery are easily accessible.
Adhesive used for the Back cover.
Screen cable and the Screen can be removed without removing too many components.