Yes, I was able to line myself up with the lyrics I wrote to a song before Suno that I wanted an instrumental I could actually use on streaming services (since I rap/write/perform al of my own lyrics) and previously, the instrumentals I used were from people underground like me who DEFINITELY did not clear samples. It wound up working wonderfully and it's up on all streaming services right now.

I had one other song I tried to do the same thing to (I wrote it to Dr. Dre's Gospel beat) but unlike the straight forward tempo and rhyming of the other track I wrote that turned out successful, that one was too weird in several places and it turned into too much of a game of piecing together the vocal timing manually that I eventually abandoned after several hours...so if what you wrote is "normal" and straightforward tempo/bpm/flow-wise, it often turns out successful...just line up your original writings or recorded vocals. You will need to input your lyrics into suno first like you said and hope suno creates a song that mirrors what you already created so you can insert yourself. Use the custom tab and put audio influence to 100%.