Iceland is now allowing anyone double vaccinated in despite their origin.You can still catch it if vaccinated. You do know this don't you?
I just had a look at a trip to Iceland, just as a theoretical exercise, in July. I'm not double vaccinated so I need a PCR within 3 days of departure (££), a flight and so on, a test on arrival with mandatory quarantine as I'm not vaccinated (who are required to take rest and only wait for result) taking up half the holiday and a PCR (££) by day 2 on arrival back in the UK. Sounds like a lovely relaxing time.