Intercepting system signal as a strategy to prevent kill calls from taking effect

As a follow up to this question, I am correct that (4) (quote below) is the farthest I can get ? > in my app (a .NET app which runs as a systemd daemon), intercept the kernel signal sent to the process upon running kill (perhaps calling sigaction) so to ignore the kill request. And that with the disclaimer of it being possible only for cases when the user calls kill either omitting the signal number or using a trappable signal (like the default SIGTERM). If the user calls kill with SIGKILL (-9) or any other non-trappable signal - this will also fall short. Is the assumption above accurate ?