Instead of thinking to investing them into something and regretting in the end, I think you should just hold your coins and go on with the flow of markets as the prices are spiking ahead slowly and there is 100% possibility for us to see it going ~$600-$700 for sure based on halving effects...
Halving may have no effect at all on the price. Although the chance for Bitcoin to rise well over 500-600$ is rather high, don't forget that it can in the same way drop a lot.
Also, I somehow believe that OP meant to do better than just keep those
BTC on paper wallets

however, it's not the worst possible option.