There are a number of different Creative Commons licenses. If you want to sell commercially, make sure the licenses item doesn’t have a Non-Commercial (NC) restriction.
Non-Commercial is defined as “means not primarily intended for or directed towards commercial advantage or monetary compensation.” So I would say hobby selling is still commercial use, particularly if sold for money.
The attribution language isn’t that hard to comply with you can review it under Section 3(a) of any of the Attribution (BY) licenses. Simply attaching a tag with the require attribution details would be sufficient, nothing says the attribution has to be permanently affixed to the licensed material, just that the recipient is made aware of the attribution requirements.
As to the open builds CNC machines. I don’t see where any CC license requires the distribution of source material. I don’t think they have an obligation to distribute dxf files.
As always, I am not your lawyer and this isn’t legal advice, you should retain a lawyer if you have concerns.