Let me get the disappointing parts of my message out first: garbage-in, garbage-out. In other words: whatever you are trying to enhance using electronics and programming needs to be good to start with. If you are still aiming for an individual performance, you don't want most of the play to be produced independent of you.
Disappointing part #2: don't reinvent the wheel. Arranger keyboards are annoyingly effective for getting complete results from just providing a single melody line and basic chord information (and in fact, that's basically the input to the purely acoustic instrument "accordion" as well). I have an old thing from the 90s here (a Solton MS80 arranger with button accordion keyboard, but they exist without keyboard/harddisk as MS40 or with piano keyboard as MS100 or as MS60 as well), and it is irksome just what kind of stuff it will crank out automatically from rather sparse input. The downside is that speed and rhythm are fixed. Once you are good enough to keep speed, they kick ass. Also, they tend to be a better Midi expander (though noisier) than what is available as cheap software.
So I'd really recommend to get something in that line, even if it's a vintage box, and learn working with it. It covers a lot of ground, it's fun, and most certainly you will get a better impression about what kind of ground it does not actually cover.
Also it helps for practising stuff with headphones in the night.
Which brings us back to point #1: whatever is supposed to be individual in your performance needs to be played by yourself, and you want it to be good. So if your work is going to end up 95% programming and 5% instrument practice, the results are going to suck.
There is other trickery people employ to good measure: distortion, delay lines, multitrack recordings, lots of stomp boxes. A lot of that stuff is quite effective, but it requires mastery as well and you won't have it do heavy lifting without you investing a lot of time and practice, either.
Also using it for masking deficiencies is coming back to bite you eventually: you'll still have to compete with good players employing the same trickery.