I have two DPS macros on two hotbar slots in-game, triggered by my one spam hotkey, then I have individual 3 debuffs on three more hotbar slots in-game (no individual keymaps for them, they are parts of the dps rotations in Isboxer). My setup has three modes -

(1) Trash. No debuffs are included on keysends from Isboxer
(2) Elite Mobs. One debuff 1 is cast before my dps macros start being mashed.
(3) Boss. All three debuffs are cast in sequence before my dps macros start being mashed.

When I switch to a new mob in Elite and Boss modes, I press manual assist keymap that resets the rotations to step 1, etc.

I use two DPS macros instead of one for spam because its easier for me to juggle spells between thos two macros to aim for a preferred cast sequence. For example dps macro 1 may have abilities that I always want to go off when they are off cd, while dps macro 2 has some ranged abilities and shorter-cd abilities. Both 1 and 2 are in a single step in Isboxer, so they get both pressed.