Missed this comment for some reasons, probably my phone and internet acting up again. But anyway, like i said, Gravity or Supergravity, in Brane Cosmology, which pretty much is the thing Honkai Cosmology follow (actually Mihoyo dragged the entire theory into the game), the specific trait of this cosmology is that gravity will work the same in all dimension, remember, work the same, mean that gravity is distributed with the same force across, that mean gravity in 1D is = gravity in 5D or gravity in 11D, etc..
Welt statement in Alien Space manga is pretty much textbook thing of this, and remember, he was a proper 1st Herrschers at that time, with a proper Herrschers power, yet he was unable to do anything to Ryusuke - an actual higher-dimensional being, even Ryusuke stated that fact, until Welt figured out how Gravity work
So yeah, you could, probably slap 1-B on SoE or even everyone who have Gravity Manipulation due to how cosmology work, but this is cosmology exclusive thing, which is pretty useless crossverse, especially with verse that do not follow the same cosmology, even with verse that have the similar brane cosmology, SoE will be limited by said verse cosmology, such as vs a verse with brane cosmology but with 10D, SoE's Gravity which is Brane Cosmology Supergravity will only be 10D because Gravity work via having dimensions, if there is no dimensions, it will not apply thus it can't be higher than the cosmology itself. That why i hesitate about putting a tier on SoE
There is another route, argue that SoE is 1-B via Honkai Energy, iirc SoE is a Divine Key so HE powered it, HE is UES so you can put 1-B on SoE. Problem is, HE is UES so you need to backscale 1-B rating to Welt physical stats, and there is a statement about him comparable to his prime but the current SoE is a replica, so idk how it is compare to the real thing