Originally Posted by
lall
I think OP is at considerable risk and may be stopped from boarding the flight in the US or even at Heathrow. Perhaps the Greece consular in US could be requested to issue him a temporary travel document to allow him travel back to his home country. The temporary travel document is a common thing and normally applies to such cases as well as those with lost passport in a foreign country and need to get back home.
If Timatic says its fine the airline will say it's fine. You might want to be prepared to ask them to look it up in Timatic - but once they do - you should not have issues at gates or check in. I have multiple passports - some were expired when those Covid restrictions on destinations started. Once or twice the check in agent had to ask a supervisor comfortable enough to read sentences exceeding 8 words - but other than that - had no issues.