I think OP need to pay at least 5 % of this amount to someone, and then he can invest in that. Like this he will just pick up some good ideas and he will not even say "tnx".
If that is mine 20 k, I would know exactly what to do. And of I would ask for advice, with that amount I would even pay for good advice.
+1
This all seems as a great way to pump your sig campaign numbers then the actual place to ask for a honest advice.
If I am wrong, I d go for a few good PoS coins, namely DMD and CLAM.
Besides PoS, you can actually start a legitimate business with that amount of money. You should buy a site, manage it, and profit from it. $20k can take you very far. You should start reading and taking courses now while you still can.