it's always good to hear, that other persons have similar problems using notes on Mac. :)
In my case I use a Macbook Pro (late 2012) and notes running without any special problems (until high sierra). After installing Mojave and starting notes it hangs. And after installing IF16 (SHF993) (without any problems) notes runs without hanging after startup.
I didn't have to change any further settings. So maybe there are other constellations that makes your macbook instable.