Amazon fit claims my 2021 Prime is not compatible with the Hella model 012010901 that I bought too. But it's already installed so I know it works perfectly.

The one Amazon recommends first as an alternate and claims as "this fits" does not have a plug that matches the Toyota harness.

On a related note, when a product claims 300dB volume, realize that is enough to kill you and everyone in a 1000' radius at minimum. It's far louder than a nuclear bomb. So you probably shouldn't trust that manufacturer's claim of "universal fit" either.

We went with the trumpet style one. Also a perfect fit, maybe five minutes to install. Obviously I can't compare it to the one you went with but it was definitely an upgrade over stock.

HELLA 012010901 Black 12V BX Trumpet Horn Kit (Toyota) https://www.amazon.com/dp/B01EG18SFM/ref=cm_sw_r_cp_apa_i_BBQdDbM0K58XY