Good, so there is no problem with
OpenCPN displaying KAP
charts, but there is a problem with either your
charts or workflow...
First of all, please turn on the chart outline display, there will be red outline around each raster chart, shown or not. Do not continue to anything else until this is the case. Check on the NOAA charts that do display.
When you are positive you see the outlines, move back to your charts, remove all the chart directories from the configuration and add one (= 1, not one and cm93, not two, one) directory where you are absolutely sure there are KAP charts.
Rebuild the chart database.
If you still won't be able to find anything, post the logfile and one, any, of those charts.