RE: Flat Tax: 5%-10%

This would be an ideal solution, make it simple so the people can understand what are their duties, don't make a legal labyrinth of it. I'm scared to take out anything of my crypto to FIAT, never withdrawn anything for this very reason. And in my country, Spain the Supreme Court took down the penalties set by the gov because they were "abusive", they're setting new ones at lightning speed though.

In the long term people will buy products directly from crypto, it's a matter of a year or two to be mainstream, so any gov that wants to take his part of the cake will need to regulate this carefully. In that sense this fixed tax for all withdraws is the correct way to go.