Trying to use an SDK on the Linux Editor

Hello community! I need some help for get working an SDK on the Linux Editor, exactly the "Fast-VR SDK"(https://github.com/relativty/fastVR-sdk), i have have installed SerialPortStream, for get compatibility with

Code (CSharp):

1. using System.IO.Ports;

(https://github.com/jcurl/SerialPortStream), and in VSCode, the errors Disappear, but in Unity, it still giving me errors.

There's any method to get SerialPortStream working in Unity?

PD: I have changed the .dotnet version to 2.0, in the API Compatibility, and it gives me an error that says "NullReferenceException"

Thanks for your attention!