Does anyone understand the rules for testing and travel to Portugal?

 We are planning a trip to Portugal in October. I am trying to make sense of the rules and what we have to do to travel. They seem to change every five minutes. I was under the impression that the UK and EU countries had a reciprocal agreement regarding vaccination status, but it appears we don't. Portugal is on the green list, but it seems you still need to follow all sorts of rules. It says you need an EU digital covid certificate. I've checked and it seems the UK NHS one won't do (although this is less than clear). It says that UK Citizens don't need to be vaccinated if we have this. It is yet another sign of the folly of Brexit that UK citizens have to jump through all manner of costly hoops to gain entry to Portugal that EU citizens don't. I can understand why the EU is cross with the UK, but surely this will be rather self defeating in the bigger picture as UK tourists decide it simply isn't worth the cost and bother of travelling. 

I fully accept and support the need to control Covid, but surely these should be based on a scientific necessity, not arbitrary rules made up with one eye on the political backdrop of relations between the two nations.