I think you need to spend a little more time figuring out how to use it. I would first plug direct into it with your guitar and into an amp to get some clue to what it’s capable of doing. Parallel processing (with mixer) takes some tweaking to get right especially with pitch effects. Try a 4 cable method. There are algorithms with multiple effects in them. The main effect will have the highest degree of quality. Having said this you are dealing with a processing unit that is quite old now. Although I still use it and so do thousands of other pros to great effect.

Did you buy it new? If so, return it.