I'm not sure to be honest, i mean im not stating that you're right or wrong but here it states
https://marvel.fandom.com/wiki/Beyonders
under
Powers and Abilities
Three Beyonders have been shown to be powerful enough to kill the Living Tribunal itself, as well as destroy every other cosmic entity of every reality.[7] One alone easily overpowered the combined might of Thor, Hyperion and Starbrand, suffering no visible damage from their attacks until Starbrand's detonation. One of them was also able to destroy the entire Fourth Host of Celestials with some efforts. Despite their enormous power, they are unable to manipulate time.[8]Cosmic Cubes were artifacts associated with them and drew their power from the Beyonders, allowing them to reshape reality.
so it clearly states
Despite their enormous power, they are unable to manipulate time.
but it also states.
Cosmic Cubes were artifacts associated with them and drew their power from the Beyonders
so apparently cosmic cubes drew their power from the beyonders, that is strange seeing how the beyonder has been shown twice to manipulate time, both advancing it, and rolling it back. (see my earlier post, i posted the links). but it's strange because the cube drew power from the beyonders who could not manipulate time, and yet the beyonder could and the beyonder came from the cosmic cube.
it states he came from the cosmic cube
https://marvel.fandom.com/wiki/Beyonder_(Earth-616)
under Secret Wars 3 it states
After barely succeeding with the help of Molecule Man, he was told that his creation was actually the result of the creation of a faulty Cosmic Cube by the extradimensional Beyonders
and it also states here
https://marvel.fandom.com/wiki/Cosmic_Cube
under
[1]Before evolving into Kosmos
- Main article: Maker (Earth-616)
First appearance: Fantastic Four Annual #23
When the Beyonder and Molecule Man were said to be parts of a failed Cosmic Cube, they agreed to be reshaped into a Cosmic Cube, which soon evolved into the cosmic entity called Kosmos.
so im not sure. it doesn't clearly state, beyonder ultipotent, beyonders not ultipotent
and since the cosmic cube drew it's powers from the beyonders. i don't think the beyonder would exceed the beyonders.perhaps equal them at best. i mean it would be strange if the cosmic cube drew it's powers from the beyonders and would somehow exceed it's source, right?
so i don't know if the beyonder would be ultipotent and the beyonders not? since cosmic cube drew power from beyonders and the beyonder (apparently) was a part of the cosmic cube.
however the beyonder could do something the beyonders could not, manipulate time, im not sure how mere time manipulation could account for ultipotence but it's something i guess?
that would somehow leave the beyonder greater (ultipotent) than the source from which it drew it's power (beyonders,non-ultipotent?) how? logic manipulation? again im not sure.
since cosmic cube drew it's power from beyonders i don't that beyonder exceed it's source, but he was able to do something they were not, time manipulation...
note:
https://marvel.fandom.com/wiki/Beyonder_(Earth-616)
twice states nigh omnipotence (if you're very powerful but not omnipotent, such as ultipotence or metapotent, i think you'd be nigh-omnipotent anyway)
Strength level
Due to his nigh-omnipotence, he has limitless strength.
Despite this, he was claimed to be either omnipotent or nigh omnipotent on different occasions, and to have power millions of times greater than Multiversal scale. Similarly, despite claiming to be omniscient, he had no knowledge of the multiverse outside of his own realm, and had to learn everything by experience.[22]
again nigh-omnipotence, but describes ultipotence (lack of omniscience)
so again im not sure.