Hi Sacco-dylan,
Sorry for the lag, I think the problem was I added a delay to check if you were hitting both the A+B buttons at the same time, but that probably felt like lag on an actually Playdate. I changed this behavior to remove the delay and just set the value of the cell to empty if you start entering noting mode by pressing A+B at the same time. I have uploaded a new version so if you re-download the game it should be better now. Please let me know if this fixed your problem. Sorry again.