Is it possible to write a song “pitch first” or “key first”?

I believe there are 3 possible main elements to a song (not minding dynamics, articulation etc):

1. The Type of Sounds + their order & The Amount of Sounds (Vowels, Consonants & Syllables & Indefinite or Definite Pitch)
2. The Lengths of the Sounds
3. The Pitches

I’ve been contemplating over the different orders songwriting could be done in, and while going through the possible orders, i’ve began wondering if a song could be written “pitch first”. In other words, how would writing pitch first even work, does anybody have experience with this?

Now, i’ve never written pitch first, I primarily begin with lyrics first and then work on the lengths of the sounds and then finally the pitches. If I do use an instrument, I typically begin with a rhythm first and then work out a melody.
From my contemplating, I would imagine “pitch first” would imply mapping out the pitches that will be used with no order to them yet, no note lengths and or course no lyrics yet (the type of sounds). I could also imagine thinking of a key first and limit yourself to writing with only those notes being described as pitch first, but I’m incapable of hearing keys before a song being performed. I’m thinking even if I could write pitch first, it would be the hardest way make music anyway.

Lastly, I understand that when we are writing, more than one of these elements can be written at a time but that is not my purpose in asking this question. I’m not really much of an instrumentalist. I write lyrics, turn them into melodies and write the instrumental parts around the lyrics (chords as well). So I’m just trying to see how beginning from the opposite end of the spectrum works.