Thanks a lot for you comment! That half/triplet/quarter build up, I have to admit, was heavily inspired by "White Leaves" from the "Rings of Power" OST from Bear McCreary, which is my favorite music of the series, I think this way of building up is absolutely genius and I was always looking for a way to try it out myself.
Concerning the drums, you can also check my answer to Aesaire, but to put it as an image, I usually think of the drums as the stairs that pave the way to that high tower (which is the climax or the next part of the song), while the instrument and melody is the helping hand from a friend that takes you there.