I will strongly advise that if you want to trade cryptocurrency, you should use the exchanges for a start. Unless there is a strong commission offered you in exness that is tilting your attention to them.
They are even more trusted and secure than the crypto exchanges when it comes to regulation with security and exchange commission, FSC etc, but the issues is that they are brokers meant for forex trading and any trading done on the platform is basically a future contract, while exchanges gave us the opportunity to trade spot.