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.
Just because she didn't earn in her country, it doesn't mean she's correct to not declare to tax authority if she no longer a tax resident there. That's wrong, I don't know your wife nationally, but ask her to google about tax for people who work abroad.
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.
How do you bought your coins? if you bought using Binance or any other CEX, the tax agent would find you because you need to report
gift tax.