This is too old to vote but I can comment anyway.

For investment of sealed boxes I can give you a little advice.

I bought a few boxes from the Khans block in 2014. They cost me around £55-£60 UK. I sold a couple of them recently for £120.

That's 100% profit but I had to wait 5 years or so. It's still viable as long as the game is played cardboard style.

The power nine are out of reach now. I sold my last Unlimited Black Lotus for £140 in 1997. Makes me sick thinking about it.