Why won't my iPod touch 5 update past iOS 9.3.5

Its CPU is too old for iOS 10 and above.

(166481)

You can purchase an iPod 6 which can be upgraded, or you can try to see if you can use iTunes to download older versions of the apps.

There are soem tips here

Downloading Older iOS 9.3.5 Versions of Apps ONLY Available Now for iOS 10 or Later

It is possible that the developer will not have an older version available.

I need to download youtube and pandora in my ipod touch 5 but it doesnt allow me; it says ipod needs updated software but it will not update