I agree that 4K definitely doesn't equal better IQ all the time (though, if all other factors are equal, why not? You can always soften an image in post.).
My only thing with purchasing lights is that you need a fairly sizable light kit in order to be flexible enough for the different kind of projects you will want to do. Also, storage.
The way I look at it, you're going to end up renting something anyway. I vote buy the lenses (you can store in a Pelican in the closet) and rent the lights--and you can get different lighting for every project.
On the other hand, if you're doing the same kind of shoots all the time, a small light kit is super convenient.
That video is the source of a lot of misinformation. The dude doesn't know how to test lenses.
My bro-in-law bought a used Alexa with money he made shooting weddings. No shame in that work--though like you said, it is soul-sucking.
Game's advice is really good. Lenses are a great investment, and they actually do make a huge difference in your image.
Ha. Ok then.
I don't think you're actually reading what Sharad says...