On this point you need to do further research. CA does not require DMV licensing just because you are a CA resident. The state licensing requirements in the US vary by state. Unlike some state, CA does not require DMV licensing for documented vessels. I understand you can’t do USCG Documentation, but could you document the boat in Belgium, or another EU country? Then all you would need is a Cruising License.
The situation with Double Espresso was very different. Assuming DE was CA DMV licensed, you merely transferred ownership under the CA DMV. Then you went sailing and never left the US. Technically, you only traveled from one US port to another.