Properly implemented interpolation is still perfectly smooth, it doesn’t stutter.
Unity has it’s issues on stuttering, it can boil down to many things that are up to devs to fix but some of the core issues are also on Unity’s engine side, see this post here: Time.deltaTime Not Constant: VSync CameraFollow and Jitter In this kind of case, you can still work around the issue by not trusting the deltatime unity reports to you and figuring out what is the actual true deltatime you should use but this isn’t going to be trivial.