> And you need to disable all sorts of compiler warnings unless you are ready to rewrite pretty much all your code to make it nullable ref type friendly.

Not really. Just disable nullability checking — you can do it project-wide by removing the Nullable tag from your .csproj, and you can continue ignoring nullability.

> And some day those warnings will be errors.

[citation needed]. A lot of code is written without nullability in mind. That includes the .NET Core BCL, AFAIK.