I currently have the "wobble wobble wobble" and some days its better or worse, one minutes its better or worse. Likely the wheel/tires even though ive had it balanced every which way by numerous shops.

I had a U-joint develop a hair line fracture which was noticeable around 40-ish mph and was bad enough above that that I WOULD NOT drive faster than 35 to get home. It literally felt like Godzilla was chasing me down the street is shook/vibrated so bad.

Do as they said and spin the driveshaft. grab a light and inspect closely as even the smallest defect in a part spinning that fast will cause a big upset in the driveline. If nothing is seen, you can also remove one driveshaft or the other and test in 2wd/4wd to determine if it the rear or front DS.