I’m thinking more in the direction of not having keys at all for going to the next step, but having the tool do it for you. Native rectangle first lets you click a start corner, then a second corner, then a third and you are done. This wont work though with tools where there is a variable amount of things to pick/select in each step. These tool are a bit tricker to design.
If a tool has just two stages for picking objects, e.g. like a Solid Trim tool, then selecting the first object to be trimmed could just take you directly into the second stage of selecting trimmers. If you want more than one trimmer you keep click objects. If you want to trim more than one object you use a preselection (which should be mentioned in the Instructor and status text). This approach doesn’t scale to tools which more than two stages though.
Not sure if this can be applied in your tool, but it could maybe be useful in the future.