I said it can potentially be a low diff, if advanced Conqueror's haki wasn't used here.
If it was used, then mid diff.
My criteria:
No diff: low effort, no injury. Example: Zoro vs Monet.
Low diff: respectable effort was there, but no injury and overwhelming defeat. Example: Luffy vs Lucci, Zoro vs Pica
Mid diff: respectable effort was there, minor injuries in process. Example: Kaido vs 1010 Luffy, Doflamingo vs Law.
High diff: high effort, sustained significant injuries. Example: Zoro vs Kaku, Sanji vs Jyabura, Kaido vs 1026 Luffy
Extreme diff: maximum effort, sustained major injuries by end of fight. Example: Akainu vs Aokiji, most Luffy arc fights.
By this Zoro vs Lucci, is mid diff at worst if Zoro has only minor injuries by the end of the fight and ended with a single advanced Conqueror's attack.
It is at least low diff due to the panels you posted, because Lucci could clash with Zoro with armament haki and keep up with him in CQC.
.......
What ending would push this beyond mid diff for you?