Downgrading iPad 6

Hey, all.

It's been ages since I've jailbroken anything (like, since my iPhone 4) but I've finally bit the bullet and jailbroke my iPad 6 using PaleRa1n. It took a couple of tries, but I finally got it to work.

But now I'm stuck. My goal is to install iPad OS 16 so I still have Apple Home support, but freeing myself from the RAM hog iPad OS 17 that has made my iPad pretty useless.

What do I need to do now to download, sign, and install iPad 16 on my iPad 6?

Thanks for any pointers.