I’ve moved your post to the section on reporting false-positives. Please have a look at this post, and adjust your topic as necessary (adding details like the Rule ID, and exact versions of products used).
SonarLint for Visual Studio v4.30 is pretty old at this point (released January 2021) with many improvements since then. I can suggest that you upgrade to the latest version, v6.1, and see if the issue persists.
Improvements have been made to this rule, including being allowed to use extension methods to perform the null check. I recommend upgrading and coming back if the issue persists.