Time matters, but I would not repost the exact same video multiple times in the same day as your default. It can muddy your read on whether the creative worked, and if the same followers see it twice it can feel spammy.
I would test time blocks instead: lunch, early evening, and late evening for 2 weeks, with similar videos rather than identical reposts. Track the first 1 to 2 hours separately from total views, because that tells you whether the initial audience responded well.
Also check where the audience actually is, not just where you are posting from. If your buyers are split across time zones, a noon test and an 8 pm test may reach very different people, but the hook and retention still matter more than the clock.