Interesting, care to elaborate?
Kid Dracula is the source of Galamoth and his throne-stealing motivation. SotN devs lifted him from there, we know that. We all know that he looks like this:

But, if you played the Kid Dracula games, you know Galamoth looked like a winged alien-like creature that looks nothing like the dinosaur-like demon we see on SotN:

But the demon we see on SotN looks a lot more like this:

...The intro/manual version of Galamoth. This Galamoth appears as a boss in an earlier level in the game, and is retconed/confirmed on the GB Kid Dracula to be Galamoth's robot stand-in, not the actual Galamoth or an "initial form" of Galamoth. A construct posing as him:

Beyond that, seems to me like Galamoth has Terminator tropes going on. Sending agents into the past to kill a person (Sarah Connor/Count Dracula) so he can ensure his victory because that person's son (John Connor/Kid Dracula) defeats him in the future. Even his initial pose seems to be referencing the Terminator when arriving in the past:

(You can just barely see Galamoth stand from this initial pose on the game as you enter his room)
What I'm saying is: what if they picked this design deliberately, and this is not the real Galamoth you're seeing, much like it wasn't the real Galamoth in Kid Dracula? What if Galamoth's soul on Aria has the power to resist time alterations because it belonged to a construct made to time travel? Also, isn't it also a Terminator trope that he's an assassin supposed to be *extremelly freaking hard* to kill? Galamoth was added to SotN with that purpose, we know that from interviews.
Also, watch his death animation:

Since he's animated through the engine, it's natural he'd break into pieces, like many bosses in this game do. But notice how the fire starts to come out of his neck and from between his joints, before his head falls off, then the rest of him follows, like a construct combusting from inside? Him losing his head first also happens to robot Galamoth, too, on GB Kid Dracula:

Although, on Kid Dracula, the battle continues with him headless.
Beyond all this, on Judgment, the Time Reaper looks like a literal skeleton. And when faced with Death, who is the protector of Time Reaper's target, Death says that the Time Reaper is "mocking his visage". Death is referencing the fact that the Time Reaper is just Death's model on Curse of Darkness. But: an assassin skeleton gets sent back in time to kill someone whose bodyguard is another assassin skeleton who notes their similarity, and whose singular job is protecting the target. What franchise of time-travelling assassin skeletons has a similar configuration to this going on, I wonder?
Terminator, at least the original, is an extremelly famous horror movie involving time travel. It makes a bit of sense to me that Castlevania, rife with horror movie references, would reference this one if given the chance. And "time travel tropes" seems like that kind of chance.
Anyway, just a bit of theorizing (and a little reaching :p ), is all. If I'm correct, this could mean we never actually saw what Galamoth looks like in the main canon. The one on SotN is an agent he sent from the future, and the same happens on Judgment again.
And I say this is a robot, but I don't use this word to mean a literal machine made of metal. I mean in the sense of a golem, a magical construct avatar, something that fits Castlevania's worldview that would be capable of having a soul like the several Golems and Creatures in this franchise have. But that's the general idea.