Unfortunately, it is not possible to add a Thunderbolt port to a laptop if it does not already have one. Thunderbolt technology requires both the physical USB Type-C 3.1 Gen 2 port and the chip controller known as Alpine Ridge to function properly.
Thunderbolt is a high-speed data transfer and display interface developed by Intel. It allows for fast data transfer rates, power delivery, and the ability to daisy-chain multiple devices. While some laptops may have USB Type-C ports that support the 3.1 Gen 2 standard, this does not mean they are Thunderbolt compatible.
The Alpine Ridge chip controller is what enables Thunderbolt functionality on a device. It handles the conversion of data between the Thunderbolt protocol and the USB or DisplayPort protocols. Without this chip, a USB Type-C port can only support USB 3.1 Gen 1 or Gen 2 speeds, but not Thunderbolt.
Unfortunately, the Alpine Ridge chip is not something that can be added or upgraded after the fact. It is typically integrated into the motherboard or logic board of a device during the manufacturing process. This means that if your laptop does not have a Thunderbolt port, it is unlikely that you will be able to add one.
It is worth noting that some newer laptops may come with alternative chip controllers, such as Titan Ridge or Ice Lake, that support Thunderbolt 3. These controllers offer additional features and improvements over Alpine Ridge. However, even with these newer chip controllers, the laptop still needs to have a physical USB Type-C port that supports the 3.1 Gen 2 standard in order to be Thunderbolt compliant.
If your laptop does not already have a Thunderbolt port, it is not possible to add one after the fact. Thunderbolt technology requires both the physical USB Type-C 3.1 Gen 2 port and the Alpine Ridge chip controller to function properly.