Tax is not only an EU concern, and FluentCart 1.4.0 reflects that with built-in rates across Africa, the Americas, Asia, Europe, and Oceania. It also treats Northern Ireland as its own VAT jurisdiction, a detail that catches out plenty of tax setups.
If you need more precision, you can override tax by city and postcode, and even set tax inclusion per product variation. The defaults are sensible, and the overrides are there when a sale needs them.