Some observations.
CW decoders are dependent on what they are 'fed'. If the CW to be decoded is predictable and well formed, most of them can handle the decoding. If there is any variation in that CW, any differences in timing or spacing or length of the dit/dahs, then none of them will recognize what it's 'fed'. It has to guess at what character was sent, if it can 'guess' at all. All of those decoder programs are very easy to 'spoof', or in other words, they miss things (intentional or not). There's no substitute for using that 'computer' between your ears to decode CW. That takes time and work, sorry.
The two ways to increase your abilities is by a more complete utilization of the resources you have, or to expand those resources beyond what you have now. There's only so much you can do with a limited amount of resources, there are limits. So, the easiest way of increasing ability is by increasing those resources. In the case of what's being discussed here, that means to up-grade the license held. That opens the door to a lot of additional resources already available. (No 'magic' to it, just some hard(er) work.) Then you get to the implementation of those 'new' resources. Where the @#$$ do you put the @#$ antennas!? Unfortunately, that's not as much a joke as it sounds, and sometimes, you just can't get there from here, you know?
- 'Doc