thanks, JS
Update= today while I was banging on the rim I was distracted mid swing by my kids chasing each other right over the wheel.

I whacked 2 spokes with the rubber mallet and bent them slightly.
So I think I'll take it all apart, finish straightening everything, and put it back together.
I was worried if I beat on the rim without being laced up it would warp the hoop... but I'll try it unlaced. and see what happens.
I mocked it up on a spare axle and it spun a little wobbly, but once I loosened all the spokes it generally spun round and smooth except for a high spot to the right of the low spot I've been banging on.
I'm gonna get to that later, my wife won't let me go back in the garage right now.
I made a short video if you wanna see some MacGyver action.
(still being processed)