Having watched Eternal love of dream before watching Eternal love there are differences to the story.

Both stories are centered around the female lead primarily of the Bai/ Fox Clan.

The flaw with stories is how they jump time, its more voiced that a character is going thru a t trial, or that 1 day is 1 year etc.

In terms of the story and plot of Eternal Love it appeared more fluid than Three Lives, Three Worlds, The Pillow Book 2020 version.

Both stories ended on positive notes, and in some cases happy endings.

Changing casts for Eternal Love vs Three Lives, Three Worlds, The Pillow Book/ aka Eternal love of Dream did make inconsistencies to the story, if it was intended to be a sequel there appeared to be major flaws, as the stories can overlap, there was no need to. (I.E. Wayne Liu's character is Kunlun, but hes demon prince in Love of Dream)

Eternal love is more on a serious story note than Eternal love of dream in terms of the main character.
Did we need Dong Hua *& Bai Fung Jei 's story in Eternal Love, no. It seemed more like a filler/side story that drama tend to over use. Like how in Love designer drama, personally I didn't care for the BFF's romance, at many times it became annoying, Eternal Love didn't get to the annoying state with Vengo + Dilraba's characters, but from a script/story standpoint probably unnecessary, given that they ended up with their own story plot in Three Lives, Three Worlds, The Pillow Book/ Eternal Love of Dream, where they dive much deeper, and didn't even have any continuation from Eternal Dream.

Su Jin/ and Xuan No's roles did get annoying over time, Bambi Zhu did play similar beotch/ jealous type role in Sweet Dreams also,, while understandably Su Jin's role was she'd do anything for love, even though Yeh Hua basically figured her out the whole time, but gave her space.

Overall, it was very enjoyable to watch, more so that Three Lives, Three Worlds, The Pillow Book, even though I've been watching these fantasy dramas purely to see Dilraba's performance.