For the Portuguese, it’s basically a Wood bonus where you get 250 Wood by the end of the Feudal Age.
Not a bad Eco bonus, but not THAT strong compared to the Dravidians, Malians, Huns, Teutons, Japanese, etc.
Not to mention that some of those civs save Wood as soon as the Dark Age
As for the Poles, how much Stone do most players actually collect in a typical game?
Especially given the preference people have for open maps?
You start with enough for 2 TC’s, need 650 for a Castle, and then you have about 220 extra Gold by some point in mid-Castle Age.
That’s nice, but not OP considering the other civs with Gold bonuses by Castle Age (Ethiopians enter Castle Age with +200 of each Food Gold, Spanish can save hundreds of Gold on Blacksmith techs by Castle Age, Aztecs, Bohemians, and Turks have bonuses to mine Gold faster, etc).
***If*** the Portuguese and/or Poles are OP, it’s because they have these Eco bonuses on top of their Gold discount and Folwarks respectively, not because these individual bonuses are OP.