This puts the potential situation clearly:-
https://www.bbc.co.uk/news/business-55256248
The BBC story does however confuse "rules" with "recommendations / guidance" as it has so often in throughout this pandemic. Individual states could take a different view, dependent upon the judgement they make between the economy and public health, but their governments would be looked on rather harshly by their voters if they allowed Brits, say unfettered access to The Balearics, with the consequence there was a huge new wave on the islands.
Would I book a holiday to an EU country at present? No, still probably not. Judging by the news report I saw yesterday however, many would disagree with my position.