I am European and my wife is Latin American. She lives with me and works in Europe, since 2 years ago. She pays her taxes in Europe. However she has not declared in her country that she is no longer a tax resident there. It does not bother her, because she does not receive any income (and so no tax bills) there. There is also a tax treaty between our countries, to avoid double taxation. Therefore her country can not demand a tax bill on income that was already heavily taxed in my country.

My country imposes either a 33% or a 50% tax on crypto profits, depending on the amount of money involved. There's a tax free amount up to €10 000 of profit per year though. So I intend to cash out a small amount of my altcoins under this amount in my name, tax free.

Her country imposes a 15% flat tax on all profits over $1000 a month. It's not clear what happens if you cash out $10 000 in november, and 0 dollars in all other months. But clearly their tax rules are friendlier than here in Europe, if you have a decent amount of money involved.

To avoid huge taxation on crypto profits in Europe, I intend to send her half of my crypto portfolio.
I consider making an account for her on Binance, and funding her account with some of my crypto assets. She can cash out later this year.

If her Binance account is connected to her Latin American bank card, am I right that only Latin American tax agencies will be informed about her crypto assets/ transactions on Binance?

I don't see how a European tax agent would find her on Binance, when it is connected to a Latin American bank card and she does not have a European nationality.

At the moment she is a tax resident in Europe, but we want to move to Latin America around 2030. It is much more attractive for both of us to be tax residents there.