Isle of Man was the last EU-resident solution, and would have been safe due to EU freedom of establishment (and compatibility with EU-VAT comes in handy), but after BREXIT you can consider IoM offshore (the same as BVI/Cayman/Dubai/etc) from an EU perspective.
Non-resident Gib/Cyprus/Hong Kong/etc is also all the same 0% offshore thing from an EU perspective, its just different marketing/image.
A 0% offshore front will poke eyes out in the EU, and cannot be maintained for big business. It is also impossible to process VAT within EU like that (you can register a branch in the EU, but then its not offshore anymore).
If you have long-term big business and want to remain safe in EU (and want to have ability to process EU-VAT), these are the ultimate:
- Malta (5% effective, but warning: your 30% refund can be long-frozen before you get it back)
- Latvia/Estonia (Postpone corporate tax forever)