As someone who learned programming with scratch in elementary school, the next step they did was using DrRacket but honestly I did not like it. I don’t remember anything I made with it but still remember my scratch projects. I think pygame would be a good next step as it is batteries included and let’s you build similar gui applications with an event loop. However, I haven’t used scratch since around 2010 so it could have evolved a lot since I used it and the concepts might not translate anymore.