You can literally see here zoro with flames on sword but no lightning on first 2 panels and its in KOH mode, it follows the same panel stracture in this chapter where you see the lightning only on the last panel
You don't seem to understand. He doesn't need flames to use ACoC and vise versa.
The scene you provided shows Zoro going through the steps to reach KoH. It's meant to show us he can control the flames separately from ACoC.
In this scene, we see Zoro fighting with no ACoC, blackened haki, or flames at first (middle scenes). Then we see Zoro fighting with just flames without ACoC or blackened haki (bottom scene).
The scene showed us Zoro can fight with just flames. It's not use as a step before ACoC.
Similar to Zoro fighting with ACoC but no flames like in the following scene.
It's funny, some stated they were waiting for a scene showing Zoro not just gather flames on his sword, because some how that not enough, but also fight with it in battle. Now when Oda delivers some fans reject it because it destroyed their headcannon.
The very most you can say is there appears to be some small amount type of black lightning on his sword that could be CoA or ACoC.
It's different than the large amount of black lightning Zoro uses when he's using an ACoC attack. The scene had to show us a close up of Zoro's sword just formus to see a small amount of possibly black lightning the size of a needle.
Regardless he hasn't actually fought or attack with it.