iPod touch 6th gen battery issues

I have an iPod touch 6th generation, and it’s battery is absolute garbage and I had to downgrade back to my older iPod touch 2nd generation that lasts longer than my 6th gen. Even my dying iPod touch 2nd gen lasts longer than my iPod touch 6th gen. Only had this since March 2018 (nearly 2 years) and the battery is trash already.