Say if someone owns 10 Bitcoins which is not declared and government doesn't know about it (earned/mined etc but did not buy) and now that someone want to avoid paying tax on cashing it out. Can he simply move to countries where there is 0 tax like (UAE) specifically dubai and setup a company there and cash out crypto over years in dubai bank account and later decide to move to his home country with all that money. Since dubai has 0 personal tax and his home country can't charge tax on it because of non-resident of home country. Is this possible?
First of all, tax avoidance is not illegal, tax evasion is.
To even have a slight chance of getting any valuable advice here, you'd have to be more specific and state what's your current tax residency and include more details on how you acquired those 10 bitcoins.
In vast majority of western countries, simply owning 10 bitcoins is not something you would have to declare at all. You would have to declare and pay tax on it when you exchange it for something (e.g. fiat, goods, and sometimes, but not always - other cryptos) and make a profit on that trade.
