Marty,
with the 10$ per month Pro version of Suno you get the much better V4 engine which not only sounds better but does much better writing as well. That version supports a function called "Replace". You can mark sections of your song that you don't like and Suno will do those sections over (and over and over) again. You can also modify the lyrics in the process so it can do the section again with different lyrics. V4 also supports a "cover" function which allows you to upload your own melody, vocal or complete song and have Suno create a cover version. So if you have a rock song and want to hear what it sounds like as an R&B song, just cover it. Or you can use that function to exchange your vocalist, etc. The package also includes 2500 credits per month. That will get you really addicted.

All the best - Robert