Are you sure that you have a spark at the plug? I thought of a really dumb possibility but it is worth a try. On the right handlebar there is a RED switch above the started button. I could see in your video that it is in the run position. Have tried to switch it to off and then on again? You might try to squirt some contact cleaner or WD-40 into the switch and then move it back and forth a few times. It could be that it is corroded from sitting and I should say that this is a long shot but worth a go.
Blue, Good point on the kill switch.
Also, I like the starter fluid squirt into neck of the air intake. If that fires it up....
Then we crank it for a few seconds, and then remove the spark plug?
Look for a wet plug, smell gasoline is reaching the engine?....this is easier than removing the injector and looking for a squirt....and safer
If it stinks of fuel.....leave plug out for a couple of hours - might be flooded.
If starts with starter fluid for a few seconds and NO smell of fuel with plug removed....- then we're getting close.
Also, look for spark when grounding the plug on the head?
Stig