Ways to Make Matcha Powder Less Bitter in Baking?
So, first things first... matcha is not supposed to be overly bitter. It has a certain bitterness to it, but good, well-prepared matcha is not overpoweringly bitter. (I'm talking about the actual tea itself, not anything made with it)

I'm going to add a few precautions you should take when making anything matcha-flavored:


Make sure what you're buying is good and authentic matcha, even if it is culinary grade. 
Good matcha is very bright green and very finely powdered. 
Look for shade-grown, stone-ground matcha made of tencha from Japan. It is going to be expensive, but it will keep you from disappointment.


That being said, matcha doesn't like to be heated past 80-90 degrees C and needs to be quite thoroughly aerated for the flavor to spread and blossom. This is why the best-tasting products made of matcha are usually things that are not boiled or baked, like mousse, icecream, or cookies with matcha frosting.

Potential solutions:


Switch to a no-bake cheesecake recipe (so you don't cook your matcha)
Prepare the matcha in milk (or other very fluid, easy to aerate liquid) and incorporate that as an essence / extract in your recipe - the usual proportion for drinking is 1-2g in 80mL of water so you can go from there for adjusting your liquid quantity