Diatoms are harder than cyano in my book as with cyano you can vacuum the sand mud day removing the bacterial and whatever they are consuming. Diatoms simply don’t vacuum as well.
However, once you do manage to eliminate their food source there is not the major die off and rerelease of nutrients back into the water (at lease IME) that I see with cyano. What are you doing for nutrient export? Any macro to try and outcompete? If not it might be worth setting up even a temporary fuge or reactor. Even if you take it down afterwards. Tried changing food? How old is the tank?