Meh, I wasn't really posting this to prove Shuma > Beerus, just random wank to show off how powerful he can be. Anyways, your interpretation is sound, but as for the "destroying two suns" thing -- Gorath has that beat by a mile. As I previously mentioned, a portion of Shuma-Gorath's power that was given to Doctor Strange was enough to destroy galaxies merely by Strange standing next to them:
This is much more impressive since it's only a portion of Shuma's power and it destroys galaxies without any exertion of power. Beerus sneezing, despite it being a very small exertion of power, is still unleashing some form of blast. Strange simply has to exist and that's enough to destroy a galaxy or two, which is infinitely more impressive.
I was actually comparing Strange's performance against Galactus against Phoenix's performance; in which case, Strange came out as considerably better, hence he's a good deal better than Phoenix, who destroys Solar Systems as a side-effect of travelling.
Dormammu once believed Eternity to be the most powerful being in existance, which makes sense since at the time the Living Tribunal wasn't even a concept as a character. Anyways, in later times, where Eternity is indeed an incarnation of the multiverse, Dormammu has(thanks to Umar) reached a level where he can defeated Eternity:
And it's confirmed that the Eternity Dormammu defeated up there was actually a multiverse(multiple universes being born and dying is just a fraction of Eternity):
This is further established in The Ultimates II:
So as of now, Dormammu is capable of defeating the very Multiverse itself, or at least possesses more than 50% of it's power. Now as for the attack being suicidal... it wasn't. Though it seems as much at first glance, Dormammu actually survived, he was merely banished by the attack whereas Eternity needed to actually recover:
Dormammu never served Death, though admittedly Shuma-Gorath once did, but this has long-since been retconned. As of now, Shuma-Gorath rules a (multi)universe that's directly opposed to Death and a ritual from Shuma's followers destroyed Death itself within the Cancerverse:
In fact, the major role of Thanos in the Thanos Imperative is to free Death herself from the Cancerverses grasp, and even then Death only destroyed Shuma's underlings but not Shuma-Gorath itself. Shuma has been directly opposed to death for over a decade now.
Good thing this is 60s Dormammu, who's afterwards had a bountiful amount of extreme power-growths and as of now stands as at least comparable to Eternity, the very manifestation of the multiverse(they've always been more-or-less equals, throughout their 50-odd-years of existance). And Shuma makes Dormammu look pathetic by comparison by all accounts, anyways.
Yeah, Shuma can be banished if you absorb what's left of it's power and thus become it, something that drove Strange to committing suicide. Assuming Beerus even kills Shuma, which I doubt, he in turn would become Shuma which would still count as a victory for Gorath.
We shall see. Good luck.