It...probably shouldn't?
If we assume that Haki is the manifestation of a person's willpower, then Domi Reversi runs absolutely counter to that.
Domi Reversi forces Imu's will onto others. They're forced to obey Imu's commands. And it doesn't work like the Contracts with the God's Knights, influencing their personality. The original mind of the person is still in there, usually fighting back as best they can. We've already seen that Rocks, Dorry, and Brogy's minds were all still in there, after they were Reversi'd.
So, Haki really should work against Domi Reversi. Not with it. It shouldn't get a boost.
Unless Imu is somehow able to control their Haki, separately from their mind? Maybe Imu can "unlock the full potential" of their Haki, which is WHY they get a boost of strength? I suppose some of the powerups with Domi Reversi could be Imu forcing Haki to manifest in a completely different way that we've never seen before. I don't think that's what's happening. But, I'll throw it out there as a possibility.
If anything, I'd say Imu's more likely "infecting" people with their own Haki, rather than boosting the Haki of the people under their control. It seems like Imu has to wound their target, in order to start the Reversi "infection". So, that feels like it tracks better with what we've seen so far.
Domi Reversi seems to make those infected more demonic or draconic, like Imu is. People who have been Reversi'd usually get horns and wings, like a demon...or a dragon. But, there's also the eyes. The eyes of those who have been Reversi'd also look suspiciously like Loki's eyes in Dragon form. "Flaming" white eyes. And that's because Imu likely has some sort of connection with Dragons, too. We've seen that Imu likely has some sort of Dragon-like form back when the Gorosei fought Sabo and Cobra in the Empty Throneroom in Chapter 1085. So, when someone is Reversi'd, I personally think it's making them more Dragon-like. Explaining some of the physical buffs. Which probably shouldn't have much effect on Haki.
If this has anything to do with Haki at all, anyway. It's entirely possible this is either a Devil Fruit power, or something involving a Third Power System, possibly something involving "Symbol Magic". But, just for the moment, let's say it could have something to do with Haki.
https://worstgen.alwaysdata.net/forum/threads/imu-still-may-not-be-the-sea-god.76012/#post-6482582
So, I'm going to say no. Domi Reversi can't boost Haki like it can buff physical abilities. Rather, I'd say it more likely "replaces" the Haki of those being controlled with Imu's own Haki. It's But, we haven't seen a whole lot of Reversi, yet. So, we'll see what we end up finding out.