Isn't this literally economics 101? How did we ever even end up imagining that tariffs are somehow paid by the exporter??
No, it isn’t that simple. Who bears the most weight depends on the elasticity of the curve on each side. This is confirming demand is more inelastic, which causes it to bear the burden, but could have been the other way around.
Countries geographically closer to the USA might reason differently because close countries usually trade more and they have more to lose. But even in this case, if a Mexican or Canadian company can find other markets or discovers that it can keep selling at the same price, they will not bear any of the burden of the tariffs.
Russian like sanctions were applied to Italy about 100 years ago because of colonial wars in Africa. Despite the sanctions lasted only 6 months, Italy discovered that they ended up trading less with the usual partners and more with others. Tariffs are somewhat similar to sanctions as they apply friction to trading.