UK companies after Brexit
A GB EORI number is not valid in the EU. When a Swedish number is the right one.
GB and EU numbers
Since the United Kingdom left the EU customs union, a GB EORI number is only valid for UK customs. For customs formalities in the EU you need an EORI number issued by an EU member state.
Which member state?
The member state of your first customs activity in the EU. If your first shipment is cleared in Sweden, you apply in Sweden. If you already cleared goods in another member state, you should already hold a number from there.
Northern Ireland
Businesses in Northern Ireland use XI numbers issued by HMRC for movements covered by the Windsor Framework. Ask HMRC or your forwarder which number applies to your movement.