Let's say I setup an IBC offshore company at Seychelles. All crypto is transfered to a hardware wallet owned by the company. Is this a good setup for taxes specially considering spanish laws?
As long as you live in Spain, you have to pay Spanish taxes and so does your Seychelles IBC. Not doing so is a crime that can land you in prison for a long, long time. For now, the risk of getting caught is probably low if you exclusively deal in crypto. But if you ever exchange the crypto for fiat and want to have the wealth personally, you are at significant risk of being caught.
I'm planing to not live in Spain, as rulers are destroying the economy, unlike Germany for example. Seychelles IBC is a vehicle for this plan, as I don't do business in Spain and doubt I will, but if I do (like mining cryptocurrency) I'll open a spanish company. Sadly tax evasion is a common thing here within some limits.
Check CFC rules for the country where you plan to move to in regards to the Seychelles. Placing a company in a tax heaven︀ and controlling it from a another country will most likely trigger CFC or PE rules︁ which prevent you from legally enjoying tax free profits in the Seychelles while living some︂ place else.