Write lyrics without melody, without instrument, without rhythm. Pure text — a poem that will become lyrics later.
Turn off all music. Write the text as a poem — focus only on words, images, rhymes, meaning. Only when the text is done, add melody and rhythm.
Melody and rhythm can deform the text — force you to choose shorter words, change word order. A purely textual approach preserves language naturalness.
Leonard Cohen wrote lyrics for months before finding music. 'Hallelujah' had dozens of text versions.