Okay, I pulled the battery and had it load tested. Showed 100%. Voltage is around 13.0.
I don't hear anything when I press the starter button - the lights dim but that is it.
The plot thickens ...
We have so far:
* The battery is known-good.
* The last time this happened, the only thing you did was replace the battery, and it was "fixed".
* All pre-start electrical systems seem to respond, except of course the starter itself.
* It can't be a fuse (else it wouldn't have been "fixed" by a new battery)
* It isn't the ignition switch or starter button (because the headlights -- well, you said "dim", but the headlamps should actually go off during cranking -- do they?)
That seems to leave two things: a poorly seated connector, or an intermittently failing starter motor.
(I'm also taking your word when you say "checked" the kickstand switch, clutch switch, etc. This sounds like behavior that could easily be caused by one of those failing.)
If it were me, I'd next check all relevant electrical connectors (unplug and reconnect each), and thoroughly clean my battery connectors.