Hey dude the cryptocurrency is not just about Bitcoin only, it's not that you could buy profit just from that one. Questions aside, i personally think that bitcoin is too speculative to be to able to truly 'DIP' or 'Sell at ATH'. Bigger player are seriously fiddle with this market and you are pretty risky trying to be smarter than them, i would seriously suggest for you to look into Alts if you really do wanna make effort to be onboard x10 train.

CFD and short selling is even more risky, except you are exceptionally sensitive trader, you got the basic right and seriously there is nothing you could do if your reserve is not fat enough. Good luck in your future investment though.