Sell SPY and take the loss?

I realized about a year ago that I'm an idiot when it comes to stocks (and lots of other things), and rather than invest in random individual companies, I'd just start putting my money into SPY.

I guess I lucked out, because I would've lost even more money in recent months if I'd stuck to my old strategy, but my SPY shares are still down a few grand.

I'm an idiot when it comes to taxes too, but is there any reason I shouldn't sell my SPY shares, take the capital loss, and move the money into VOO instead? What would be the pros/cons of such a move?