I think the key is changing the angle.
From what I read, most knives come with a 30 degree angle. The sharpener changes it to 15 degrees.
Wüsthof sharpens some of their Kitchen knives at a 14-degree angle and others at 18-degrees. So it’s hard to determine the angle that disappointed you.
I hope that your chosen 15-degree angle provides the performance you’re looking for.
When reading about knife edge angles, it's important to note if the author is addressing the grind angle or the knife edge
total angle. A 15-degree grind produces a 30-degree total angle.
Under 10-Degree AnglesThe lowest angles are suitable for edges that are used for cutting extremely soft materials. The edges are not subject to abuse so the lower angle can be maintained without damage or edge failure. Think straight razor.
10 to 17-Degree AnglesA sharpening angle of 10 to 17-degrees is still quite low for most knives. With a total angle of 20 to 34-degrees, this is a very fine edge that is typically too weak for any knife that might be used in any type of chopping motion. Also, harder knife steels are are more brittle so they're more susceptible to impact damage. If your knife is used for cutting soft items or slicing meats, this lower angle can hold up and provide a very smooth cutting action.
17 to 22-Degree AnglesA 17 to 20-degree angle is best for most kitchen knives. Some knives (typically Japanese knives) are sharpened to ≈17-degrees. Most western knives are ≈20-degrees. These angles are usually not durable as rougher treatment in harder materials will turn the edge if it’s a total angle under 40-degrees.
22 to 30-Degree AnglesIn this range, the knife edges are considerably more durable. A pocket knife or a hunting knife will inevitably see abuse not seen by knives meant primarily for use on softer materials. While the edge may not ultimately cut as well (but you may not notice a difference) it will be significantly more durable.
Over 30-Degrees AnglesAny edged tool that is sharpened past 30-degrees will be very durable, but its cutting ability will be noticeably reduced. This durability has an advantage because more force can be used to make cuts. While many knives won’t benefit from this sharpening angle, a machete, cleaver or axe will.
An 18 to 25-degree edge is a good choice for the average cook. I recommend starting high and working toward more extreme angles after judging a knife's performance.
Just my