Why did my Apple Watch SE 2nd generation battery die so soon?

After having my Apple Watch 2nd gen SE watch for only a year and a half, the battery started lasting shorter and shorter, and then one day it died. Recharging it, the white apple will show up and then nothing. Took it to the Apple Store, and they gave me a ridiculous price to have it fixed. I’m very disappointed that this watch is so expensive with such a short life span.

[Re-Titled by Moderator]