@Dirtman advice is sound, just salty....as is he.
Its gonna cost money, or time....same thing
I personally try to balance between the two, and usually PITA factor is what makes a difference.
Oh and also in regards to tires I more so meant maybe one of the wheel balancers flew off and now its out of balance. I noticed they would fly off my motorcycle if I went fast enough and did't duct tape them down. So now on my vehicles I usually drop a little super glue on the outer weights and a layer of duct tap over any of the stick on weights.
Anyways look for any evidence of missing weights (shape marks, fresh peeled tape etc)
If you see anything suspect, have a tire shop throw it on the balancer. If you have more time that money you can probably find a new or used manual tire balancer cheap.
If you havent already, maybe try just rotating the tires, perhaps that can at least help track down if its something else.
I think probably tire issue, but/and also something else that cause the tires to become an issue, maybe shocks?
This is one of those it could be anything, but also lots of things you can do to figure it out. I'd keep messing with it.