Effects of longer and higher stem on rider position/comfort and handling
There is no magic formula for handlebar position, so some experimentation is necessary.

If you feel your hand should be further forward, get a longer stem. Think about where your hand want to be on the drops and decide if you will go 1cm or 2cm longer.

You can experiment with bar height. If you have spacers on the steerer you can move the stem up and down. If you want the bar higher still you can flip the stem.

By the way, many riders find the drops uncomfortable for long periods of time. Spending time in the drops, stretching and core strength exercises help.

With regard to handling a longer stem moves mass forward which makes the bike a little more stable and slows steering due to the longer radius between contact points on the bars and the steering axis.