Irelands not good enough IMHO
There can be no legal agreement between the European Commission and the US that *reduces* the basic privacy right because they're required to uphold that right. So this attempt at stripping the privacy right is a clear fail.
Without the EC's attempt, then US companies have to obey the same rules as every other company. Either : a) host their data in Europe and comply with EU legislation, or b) show that they can comply with EU Legalislation in another country outside the EU.
With USA asserting rights to grab data worldwide from companies, outside of the proper territorial treaties, no US company can comply with EU legislation even if they host the data in Ireland. Because as long as US parent corp can access Irish data illegally then they're still not complying with EU law.
So Microsoft are fighting a demand for data it holds in Ireland (it holds UK Parliamentary data in Ireland too). But even if it wins, as long as other companies in Microsoft can access that data, then Microsoft can be compelled to hand over the data outside of the EU laws.
The Theresa Mays and Diane Feinsteins of this world might like to think it will only be 5 eyes countries that grab the data, but that's naive. China and Russia have leverage on Microsoft too, and both are passing data grab laws.
Technical protections, strong end to end encryption, legally separate data holding companies in each jurisdiction, need to be put in place so that corporations won't go handing all our private data over to ever junta on the planet. That's how they can comply with EU law.