My AirPods only work 30 minutes once fully charged

this is absolutely not normal, but, i'm afraid, there is nothing you can do on your own.

are pods on warranty? if so, bring them back to shop, if not - look for authorised service, maybe they can repair

and, btw, you can get "battery service":

https://support.apple.com/airpods/repair/service

you're not alone.

read this: https://www.washingtonpost.com/technology/2019/10/08/everyones-airpods-will-die-weve-got-trick-replacing-them/?wpisrc=al_trending_now__alert-economy--alert-national&wpmk=1

how old are those?

mine are ~1.5 year and i don't see decrease in autonomous time despite hard use in very different environments, from office to skiing in -15C...