I agree with Larry, using high P (the middle number) when not justified by a soil test is not a good idea. Also it's questionable how much difference it might make to the number of blooms because the scapes start forming months before, often the previous fall. Exactly when the final bud count is determined though we do not know.
In the absence of a soil test I would go with the 21-5-21 since you already have it but a ratio (not necessarily analysis) nearer to 4-1-2 or 3-1-2 is often recommended for daylilies and that should be fine for all applications. When you've used what you have you might want to look at a slow-release fertilizer so that you don't need to make several applications. Nitrogen is the nutrient most likely to be in short supply but any element, even a micronutrient, that is below optimum could negatively impact the plant's performance. People are often surprised when they get a soil test to find that at least some of their nutrients are way too high in the soil and they are told to stop applying them. If you apply too much of certain nutrients it can cause a deficiency of other nutrients.
Edited to correct typos - I'd add rolling eyes emoji but can't do that when editing
