Hello avincent98122.
I was aware of the 3D printed items that are available, thank you. Others for sure would find your information useful. You and others may want to check out 3D Printers at libraries.
The extended antenna modification of my contact sensor worked for about 6 months until it failed due to faulty soldering. Instead of repairing the broken solder joint, I tried a different approach by extending the magnetic reed switch instead of the antenna. This approach has more useful applications and does not alter the sending frequency of the antenna.
You may be interested in the external reed switch modification I made for my mailbox contact sensor.
Here the link:
Thinking outside the metal (steel) mailbox - 2
and
Contact Sensor Modified - Magnetic Reed Switch Remote / Outside
I mentioned above that the external reed switch is a more useful modification see the below link for another application:
My Wyze Smart-ish Lock Another Approach
Til later Victor Maletic