Hello,
What type of file do you have for the library? The .a extension or .h?
The steps mentioned in Chapter 2 "adding user static library in user application" Page 5 from How to create and use static library in MCUXpresso IDE still apply for newer version of MCUXpresso IDE, the windows shown in the guide are the same in recent version of MCUXpresso. Do you have an issue with a step?
Also could you help confirm which version are you using?
For the SDK; I see you wrote "SDK_2.x_" could you confirm which older version are you using? You could update to use the recent SDK version 26.06, you can download it from SDK Builder
Best Regards, Luis