With 10.6 million population and 290 billion dollar GDP they are similar to Greece in population and 20% richer in GDP.Portugal don't have the money, manpower and expertise to operate 6 large frigates. Their tenders are always slow, small and take years to conclude with everchanging requirements. Present Istif with Euro equipment for Portugal do make sense. I expect to see 1-2 F110s for commonality with Spanish, and 2-4 other lighter designs to be picked, with very possibly seeing just 2 F110s and cancelling the rest, restarting a light frigate/heavy OPV program instead.
I guess their naval security is not amongst their priorities. But being a NATO member country and having to spend 3% to 5% of their GDP on defence, they are “expected” to spend between 10 billion to 14 billion dollars on defence every year.
They do have few good shipyards that build naval vessels. But as you say they are slow and their naval investment program seems a bit anaemic.
It is a shame to see such a once powerful seafaring nation to be in such pitiful state. From late 1500s to late 1600s the Portuguese navy was probably the most powerful navy in the world.