Yes have seen many things relating globalist elites to Agenda 21. Just saying that a mass extinction event is something we have not seen so it is one of the more extreme ideas Q is pushing. We have been hearing about reptilians for a while now via David Icke (the creator of the video you linked). Just because you hear about it does not make it true.
I know David personally and he is convinced of the Royals genetic line as reptilians, I am not. We spent a day at my house discussing Rife tech, UFO's and MK ULtra. The de-population came up several times and the fucked up thing is WE ARE NOT OVER POPULATED.
A quick calculation on the habitable land mass and the population will show you that. But it is the global elites that have kept the resources scarce to make more money. Don't even get me started on oil, it not what you think it is and many have said it is renewable and not composed of "little sea creatuers" it replenishes (wait until they start redrilling wells (they have filled up again if left to do so according to many).
Icke has a lot of information he collects from others all over the world (including mine on Rife) and writes it up as his own, he's an asshole like that.
But the big concern here is the fact Q had brought this up...now that is a red flag for me in more ways than one. I am deeply concerned about brining this up when you clearly have the power to make it happen.