Hard to tell but are those the dirt cheap aliexpress wheels? There’s nothing wrong with them but helps to qualify.
I would assume with that kind of wobble there’s a strong chance the bearing seat its-self is a bit off and even your new bearings wouldn’t solve that issue. Is it just the one wheel or all of them? Does the whole speed ring/bearing/spacer/bearing/speed ring/bolt assembly feel good? Is there any play in the wheel once it’s installed? Like sideways wiggle or rattling?
I’ve found with bolt through pulleys its actually sometimes productive to loosen them off a bit and take the board for a short spin and then tighten them back up again, this seems to help the pulley sit straight in some cases. Don’t forget to tighten in a star pattern and not around the clock.
Yes, the vendor is janux/marc tran. I’ve had serious issues with his drivetrain because I didn’t think I needed to disassemble and loctite the screws, but now im thinking this wobble has actually caused the issues with the idlers i’ve had.
I’d also second the try without the wheel mounted just in the interest of ruling out/ruling in.
The pulley and adapter are milled from solid POM. I really doubt that’s where the problem lies.
I have some scrub wheels which do pretty much the same thing. You can work around it to a degree by ensuring bearings are fully flush in their seats & torsioning the bolts one by one, like bicycle spoke tuning to run the wheel true
Edit: I got it wrong the wheels are made by marc, I think he will help you