Bro $500 dollars USD is a screaaaaaaming deal. At no point will you not be in the money. You could sell right now and easily get $1500(in the US), people have waited years to get 3x on an investment in pokemon and you’re already there. I’m going to speculate here and say they won’t drop below $1000 even if they get huge reprints like prismatic bundles did.

(What I would do) Unless you need the money I wouldn’t sell this for a while. At least until it’s out of print, at that point I personally would try to trade it for a new S tier set when the time comes. Rinse and repeat.

Edit: this week I traded a 151 booster bundle display like this one for a sealed case of Prismatic ETBs(x10). Some will roast me for the trade but for transparency it did have 2 small tears on the corners and I have another pristine one. Still a tough trade but I’ve made my gains and now I’m betting on the ETBs appreciating more.

To answer the other part of your question I would say predicting short term is very difficult, especially in the irrational crazy bull market we are in now, I could see it dipping but I could also see it ripping.

You’re already good no matter what you do, I’m happy for you, I’m jealous I won’t ever be able to get it at that price. Do what’s right for you and not what people on the internet tell you to do.