Welcome to the Forum. Keep working on step-ups. If you can, work with Marshall away from his cage; that often works out better for step-up training. Be patient and don't give up; sometimes it can take a while for a parrot to catch on to what you want him to do, and parrots can often be reluctant to cooperate.
You might need to show Marshall how to play with his toys; it's not instinctive for parrots to play with parrot toys. Sit where Marshall can see you and play with some of his toys while he watches. Act like you're having lots of fun, and before long, Marshall may be ready to join in, or play on his own. If that doesn't work, try some different things for him to play with. My QP Ralph likes to build with thin wooden dowels, about 9 to 10 inches long. He isn't interested in building a Quaker nest, but enjoys arranging and rearranging the sticks inside his cage. Marshall might like to build too. Experiment a bit with things that Marshall can build or weave with or just chew up, and you should find some that will keep him occupied.
Welcome to the forum! Like cnyguy said it all takes time. Casey doesn’t really play but he is good at chewing his wood toys into tiny pieces to fall on the bottom of the cage. That’s how he keeps busy.