It sounds like the property you have in mind might be a holiday property. If so, it won’t satisfy Revenue requirements. Any property you buy, whether in Ireland or overseas, must be totally arms length. Whatever about buying a commercial property, buying an apartment (particularly overseas) is very problematic. A rental agreement would not be sufficient, as most such agreements tend to be for a limited timeframe. In addition, most Pensioneer Trustees tend to be reluctant to buy overseas property , not just from a Revenue perspective, but also because the administration is more complicated and more expensive.
As for crypto, I am not aware of any restrictions, but clearly they constitute a more risky investment. Again, it may depend on whether the Pensioneer Trustee is happy to hold such investments