You are essentially talking about learning modes. I would say this. "Set your chord progression to play in a loop and just experiment with playing scales using those modes."

This is all really just experimentation. There are no rules. You play what sounds good to your ear since it's your song. Put accidentals in where "they" say naturals belong. Flat a note "they" think shouldn't be flatted. Rely less on tools and use your fingers and your ears.

Remember one thing. The sense of accomplishment is supposed to belong to you, not a tool that did the work for you. I used to tell a joke in my routine about "Self Help" books. If you read something in a book and do what the book tells you to do, doesn't that make it "book help"? You didn't help yourself. You let the book automate you and convince you that you are helping yourself.

Joe, as I tell many others, the way to learn music is to learn music. You are retired now. That would imply that you are also in the age range that is considered "senior". That means you can audit college classes for free. Do you have any colleges near you? Go audit a music theory class. If I recall you are in NY somewhere. I'm guessing a state that size will have colleges of every level just about anywhere. You don't have to go to Juliard. "Bob's College" teaches the exact same scales and modes as Juliard and Berklee. Once oy learn the basics like the steps of a scale much will become clear.

I heard you say you are now "free", meaning retired. July was 10 years since I retired, and it is glorious. Retiree is the best job I ever had. Retirement gives us time to do things we want to do. For you that is learning music. So just do it. You won't learn working theory in a week or two, but in 6-8 weeks you should have a working grasp of what a major scale is relative to a minor scale (modes), why chords work together (circle of 5ths) and possibly (and I suggest this) follow up that 12 weeks of a theory class with a music appreciation class (which is widely misunderstood by most) where you will hear how those basic building blocks apply.

I once "acquired" a full copy of the score to Mozart's "Eine Kleine Nachtmusik" (A Little Night Music). I went to see The Cleveland Orchestra perform it at our outdoor venue called Blossom Music Center. I spread out a blanket on the lawn seating, opened up the suitcase, and followed along as they played. A woman behind me tapped my shoulder at intermission between the 2nd and 3rd movement and said "You actually know what all that means, don't you?" while pointing to the music. I just smiled and said "Yeah I've been doing this for a long time." She then said "I always wanted to learn how to play piano." I paused and said "And? Go learn. You want to wait until your deathbed and say you always wanted to learn how to play piano? (Pointing to the stage) Not one of those people up there came from the womb knowing how to play. They all had a day one. So when is YOUR day 1?" She asked if I could recommend a teacher. I handed her a card and said "Call me tomorrow and we can talk about it then." She called me. I found out where she lived, suggested exactly what I said to you. Go take a music fundamentals class. THEN after you see the ins and outs decide if it's for you. She went to community college for 2 quarters, then on to a private teacher, and a year later called me again to tell me she is now playing piano reasonably well enough to play at family gatherings.

That should be your story. Now go tell it.

Software won't do it for you. We, by forum postings, CAN'T do it for you.