Sounds like your compositional technique is similar to mine. The timbre of a sound influences how I play the sound on the keyboard and that becomes the starting point for the riff/melody/chord progression.
I sometimes find that fast playing can confuse the Monomachine (odd pitching - rectified by hitting the stop button!).
I have learned to adapt my playing technique to compensate but mainly I think of what I would play and just step record it (not the same as grid record), though you have to use the arrow keys to jump a step (it would be nice to be able to assign that function to a midi controller). I think the Monomachine responds better to being sequenced.
You can always play in chords (grid and step record modes) but the resultant chord will only be acted upon by the arpeggiators (cycling the notes of the chord) or if you put the Monomachine in Poly mode.
Note that if you record live everything is hard quantized (16th or 32nd) and it doesn’t record velocity (fixed at 100 but can be subsequently changed using parameter locks).