That makes sense to me and is one of the two main ways I view Ysmir. Which starting with my favorite are:

1.Ysmir is mostly a creation of Shor and Kyne(husband and wife birth a demi god) working against the dragon. Dragonborn were initially called Shor's Tongue and were at their core-incarnations of shor as Upstart who were blessed by kyne's breath with the storm crown/storm voice. And Shor is uniquely able to bestow on those with his tongue the ability to absorb dragons souls as befitting shor the ultimate dragonslayer.

2.Because Shor and Bormahu are two parts of one whole dragon-Ysmir reflects this and is able to devour dragon essence. In redguard myths the dragon is comprised of the flesh that eats/creates space and the hunger which allows it to know itself, but also causes the flesh to eat more and destroy itself/begin anew. The flesh is Satak, then Sep and the hunger is always Akel. Applying this to shor/Bormahu or Ysmir and we have Shor/Upstart as the flesh of the dragon and Bormahu as the hunger-dragon soul. The two are interlaced though as we see when a dragons soul is absorbed it's flesh disentegrates and is absorbed as well as the soul. And it is this hunger(ambition) that drives the dragon mad as we see in Alduin who dooms himself when he tries to rule the world instead of restart it.

In truth I think it's a mix of both. I think Shor and Bormahu are one entity that presents itself and likely believes itself to be two warring entities. So it is correct to say that Aka and Lorkhan are one but also correct to say that Shor does actually fight against the time god. The worldskin known as AkaLorkhan is a dual natured,split personality, insane and amnesiac God. Who by the power of his own belief and mortal belief presents himself as two singular entities at war when really the dragon is one and eats itself. Ysmir illustrates the truth of AkaLorkhan:he is dual natured and a dragon eating dragons.