Hi Rafael,
As mentioned above you can merge the references from your Drawing models into 2D files. To avoid changing the existing Drawing Models that you may wish to go back to if your 3D model changes before your project is complete, reference each Drawing Model that you wish to make independent into a new 2D DGN (either one per drawing model or just reference all of them onto one new file, that's not industry best practice but may be convenient in your case).
Ensure the reference nesting is on and set to the correct nest depth to show the Drawing Model contents.
In the reference dialog, right click on the referenced Drawing Model (or select the list if you have multiple attachments) right-click > Merge into Master.#
Tick both boxes in the Tool Settings dialog:
Then datapoint (left mouse click) in the correct view to merge from