iPad 9 takes HOURS to charge after battery dies

My iPad 9 behaves perfectly fine, the battery life isn’t anything unusual (I’ve never replaced it) and it performs well in pretty much whatever I need it to do

However .. recently the iPad will take upwards of 6 hours to just power back on after the battery goes flat. This started like 2 weeks ago and I’ve never needed to charge it that much just for it to POWER ON ???

And even after it turns on the battery is at something ridiculous like 3-7%… AFTER HOURS OF CHARGING

I assume it’s a battery issue but just asking here if there’s anything I can do without getting it to a shop because it’s fine otherwise

It’s the iPad 9 64gb model and is running the iOS 27 developer beta 1 and I’ve had it for 4 years now