you should try to get into coding such ideas yourself, to check them out & use them yourself, maybe sharing then or whatever when you know they rock.
there are some ways that don’t even cost you money, just a lot of spare time, like protoplug, or more complex environments like csound, supercollider and theres even more, if you pay some you can get even more powerful tools. you don’t have to be a full fledged c++ coder to be able to try out dsp ideas. It is just that the same stuff will most probably use considerably more cpu or contain cack errors, bugs, glitches, non-pristine-quality etc if you are no guru in dsp coding. it will take quite some time and dedication to get you going, but using such tools, less than if you wanted to code complete c++ vst effects. then you can try out your ideas, how well they work, use them in your creations, sell them to the renoise crew with actual working code and examples, whatever.
In the example I made, pitches are not shared among the playing voices. If they were, entering 3x the same note would simply increase the volume - as they would all play in perfect unison. But obviously, they don’t, so pitch is affected by the random LFO - as it should be.
I think you’re looking for something else, a way to randomly offset the sync of the waveform. This is not easily achieved in the Renoise sampler, and involves starting the sample with a slight, random offset. The result is that the combined sound of multiple playing voices doesn’t (necessarily) start at the same position and thus, you are not as likely to hear the “phasing” sound when the notes are initially triggered.