Summary
By now, you should be able to upgrade and enlarge your 3018, or even have it fabricate parts for a complete replacement of itself. There are a lot of designs on various sites (Thingiverse, Printables, and Cults 3D) for various CNC machines. You can pick one that suits your application and budget or design your own. Unlike the 3018, you now are not confined to a single motion system or even an electronics suite. Once you have established your requirements, you can move ahead with your build. As you have seen here, it is also possible to have a machine make its own upgrade parts in a steady path toward continuous upgrades.
You also have learned the potential of scaling up your capabilities to run multiple machines concurrently and establish redundancy in your shop. We also touched upon the benefits of sending off some fabrication to a third party, just to make larger parts before you refine and rework them further.
As we approach the end of this journey together, we can...