Seems wrong that Ireland cheated the system to attract tech companies then also gets a huge payout.
It's supposed to work against them, as a chilling effect for any company trying to work EU states against each other for preferential treatment. I'm sure Ireland will argue that they'll offer any multi-billion multinational this sort of treatment, but that's really the point. The EU doesn't want a race to the bottom and if EU-local businesses are unable to leverage this sort of accounting break, it's a massive leg up for external businesses.
While this is a large lump, this fine covers a decade of accounts, and this final decision comes 32 quarters after the original fine. Each of those quarters could have paid this off from flat profit. They're doing okay.