The U12A and E34 are both too new and the U12A too expensive for that. That said, they're not even close to positioned in the same category. The former weighs 1.2kg, has 7 heatpipes, and takes the fight to the D15 while being much smaller. The latter weighs only as much as the former's heatsink, has 4 heatpipes, and is priced and positioned to beat the 212 EVO.
All the run-of-the-mill open testbench reviews conducted so far put the E34 Duo almost on par with the Dark Rock Pro 4 in performance but obviously far inferior in noise. That's still within striking distance of the D15's performance, which is roughly equivalent to the U12A outside of noise. IMO more mass and 6+ heatpipes generally makes for more consistent performance on Ryzen, in closed cases.
But the reviews are done on Intel so if you are using the cooler in question on Ryzen 3000, you probably do want as much heatsink mass and heatpipes as possible to soak up the heat from the rough idle, fan curve tricks notwithstanding. That, and the A12x25 on the U12A is generally known to be inaudible at lower speeds. But I mean, there's also something to be said about a cooler that's competitive with the DRP4 while only costing $50-60. The U12A is around or above $100.