It's confirmed that when you use strong haki your devil fruit properties are maintained. It seems that when you have stronger haki and are being attacked, you still "take damage" but it's not damage done to your true body.

Oda spelled it out for us in Luffy vs Doffy. When Luffy is attacked, Doffy's kick infused with armament haki bounces off. Because it does not strike Luffy's "true body" as any other haki attack should.... this is because Luffy defended with stronger CoA

We also see Katakuri using this property while attacking. His arm is covered in CoA haki but still sticky!

We can infer that when a strong character like White Beard Divison Commander, Rakuyo, attacks an Admiral he should be strong enough and smart enough to use haki. However, Kizaru still turns into light. It seems odd at first, until you realize it's obvious. Kizaru's CoA haki is much stronger and this same property is applied. So his body still acts like light.

Again we see Jozu clearly destroy Aokijis whole entire body! It literally shatters. And we know for a fact Jozu is using CoA haki. Yet why is only Aokiji's lip bloody? When we see Aokiji's core is what is struck???? Clearly because of the same property. Aokiji's CoA haki is confirmed VERY strong per Garp fight. It would make sense for Aokiji to guard his core with CoA blocking all the damage from Jozu. But his face still got scratched by Jozu where he must not have been guarding as much. Thus Aokiji's body turned into ice and took no damage, while his face still took damage.

This ALSO explains Morley versus Ryokugyu where we CLEARLY again see Morley's spear inhaling Ryokugyu's hand AND chopping off his arm. Yet!!!! GB is completely undamaged for his "true body". Because Morley's haki is weaker than Aramaki's CoA.

Aaaaagain. We see Rayleigh, a haki master, slice the light body of Kizaru. Yet Kizaru is alive and well after the fact when he should be cut in half! This is because Kizaru's CoA is stronger than an old Rayleigh. And Kizaru is stopped from moving forwards clearly because Rayleigh used his haki to chop off the light! Kizarus body turned into light but took no damage. This property COMPLETELY explains this scene.

Now for the good one! Everyone is always confused by Akainu complaining about Marco and Vista haki. If Akainu dodged then why is he stumbling backwards? Why does Akainu have actual gashes in him? Again it's the same principal. Akainu's CoA is a tier above Marco or Vistas and so when his body is struck by their haki attacks, it just turns into lava. And Akainu's true body takes no damage.

This also might explain why Pizarro's hand is not actually shattered despite Coby's honesty impact obliterating it. It would make a lot more sense of Pizaro's haki was still well above Coby's haki since he's an infamous level 6 pirate and commander while Coby is just discovering his talent. This one may also be just how Pizaro's df works. Hard to say for sure....

Finally we see g3 Luffy use elephant gun on Kaido in act 1 who is knocked down out of the sky. Yet Kaido takes no damage from this.... clearly because Luffy's basic haki is not strong enough to bypass Kaido and touch his "true body" so it just hits the dragon scales instead and pushes Kaido. This is also why you need Ryuo to even damage Kaido! Because his haki is so strong that no amount of regular haki will overcome Kaido's defenses. They literally need to be bypassed! Via ryuo.

Hopefully this clears up a lot of scenes that don't make too much sense!