What is the most accurate way to call a function based on time?

I'm making a sort of music game where you need to spin a crank with the BPM. I was originally using a simple Time.deltaTime timer on every update, but after trying to sync it with some music I noticed it was quite off most of the time. I've changed the code to InvokeRepeating but the timing is still off. How my code works is basically:

 Stopwatch timer = new Stopwatch();
 
 void Start()
 {
     G.beatDelay = 60 / BPM; //this gets the time between 2 beats on a given BPM
 
     timer.Start();
     InvokeRepeating("BPMTick", G.beatDelay, G.beatDelay);
 }
 
 void BPMTick()
 {
     sfx.Play(); //play quick metronome sound
     Debug.Log(timer.ElapsedMilliseconds); //showing me how accurate the timing is
     timer.Restart();
 
     G.beat = true;
 }

Essentially, set the variable G.beat to true when a beat happens, set it back to false the next frame. But my biggest problem is executing this code accurately. InvokeRepeating is the best option I know, but it still has a delay of around +4ms and sometimes can do -5ms or +20ms, which makes the metronome sound wonky. The difference also adds up over a few minutes or so. I also tried using FixedUpdate but got very similar results.

Is there any way to execute the code with a + or - 1ms difference? It seems a lot to ask but maybe you C# magicians know how to do this. Thanks!