There have been several threads on this topic this year.

In brief, for me, most of the time the initial idea for the chorus and the basic chord progression comes in a blinding flash and I reach for the tape recorder or phone to spit it out, singing the lyrics. I know what progression I am singing. That is easy to decode.

At that point I am 75% done.

Then I will work on refining the lyrics, then the music (or the reverse process) and then bring them back together for a final polish.

I cannot write music separate from the lyric idea. They are like two buckets that get pulled out of the same well at the same time, sloshing all over the sides.

That is the best way I can explain it. They are intertwined from the beginning.