Okay, Christian. At first glance, it it is bending mostly near the handle. You'll need to get more of the limb to take the bending load. If you were to divide your limbs into thirds, it appears that the 1st thirds from the handle are doing most of the work. From the one picture, any corrective measures would be wood removal in the nextt 2/3 of the limbs towards the tips, stopping short about 3-4 inches from the tips.
With as far as you are pulling it back, you should be able to shorten your string to a normal brace height of "about" 7-inches measured from the back of the handle.
Do you have a bow scale set up on a tillering tree or wall? You need to know how many pounds you have to "mess with." If you do and can hang the bow up, at normal brace height, draw the bow without exceeding your intended draw weight. Record how far (in inches) you were able to draw. If for example you were looking for 50# at 27-inches and your bow so far pulled 50# at 20-inches, you know that you have 7 inches remaining to reach your draw length. Remove wood where the limbs aren't bending. If/when the arc is good, remove wood evenly along the entire length.
The closer to the handle that you remove wood, the quicker you'll lose pounds. You seem to be bending sufficiently just outside of the handle areas, so make corrections in the 2nd two-thirds of the limbs.