Ive read that he stays the same in terms of difficulty, that he doesnt get more damage or health unless you try the Uber version.
Is this true, can I push Monoliths up to 1000+ but normal Aberroth stays the same in terms of difficulty?
Yes. If I remember correct, Abberoth doesn’t scale with corruption at all. Both version have their own set difficulty balance.
Maybe someone will correct me if I’m wrong.
Both Aberroth and Uber Aberroth are static fights, there is nothing that impacts them in any capacity.
The Uber Abberoth inside the Threshold of Eternity Woven Echo (the one that drops Shattered Worlds) at 1000 corruption is definitely tougher than the Non-Uber Abberoth at 300 (the one that is at the end of the empowered timeline map / Altar of Oblivion). It may be related to the Threshold of Eternity itself than the corruption level though (it is as hard at 500 vs 1000 corruption).
If you are talking about whether the non uber abberoth in the Altar of Oblivion gets thougher if one of your timelines is at 300 (first unlock) or 500 or 1000 corruption, then nope. The difficulty of that altar is static.