iOS/iPadOS sets invalid ipv6 router address [no connectivity]

Hello,

I'm having trouble getting ipv6 connectivity on my iPad Pro running iPadOS 13.2.3

The device successfully pulls a valid ipv6 address 2600:xxxx:xxxx:xxxx::d, has the correct manual dns server 2600:xxxx:xxxx:xxxx::4, but the "Router" address that it pulls fe80::xxxx is not a valid address; it cannot be pinged from any device on the network. The Router's ipv6 address on LAN is a 2600:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:f274 address. That address is displayed on my router's ipv6 page and is input on all of my devices. I have 30 devices on my network, a mix of Android, iOS, Windows, Mac, Linux, game consoles, streaming boxes etc. and the only devices having issues are those running iOS and iPadOS.

Normally, this would not be an issue as one could just manually configure the ipv6 settings and the router address. However, for whatever reason, Apple does NOT allow you to configure the ipv6 settings outside of setting the dns server.

Am I missing something or is iOS/iPadOS's ipv6 implementation poor? If you can manually configure ipv4 there is no reason that you shouldn't be able to do the same with ipv6. Am I stuck with a ipv4-only device or is there a way to fix this?