Here is my take on this.
I love purple and it's a good color, but the idea of "purple Portugal" because you will be able to differentiate between other countries more quickly is a bad one. That's simply going too far. You can't prevent it, if I as Spain get a treaty port from Qing, I now have very "similar" yellow provinces at the map, I need to pay a bit more attention to differentiate/notice the diference between the 2. Does this mean we should change Spain color to pink to make it easier? No. Does this mean we should just say "fuck it" and choose any color and suffer with too many countries with the same color scheme? Also no.
What we should do is a balance approach, where we take the historical colors that represented/associate said country and display on the map that color (its called political map mode for a reason), if it's too similar or the same to a neighbor country, you can "change" it, like the tone of the color... (that's what happens)
So purple for Portugal is a bad idea. While a great fix to make it easy to tell "HEY LOOK, IT'S PORTUGAL OVERTHERE", It has no historical bases where you see Portugal identity being associated with Purple. It's too radical of a approach.
It's a really random color too. It's like going to Bavaria and changing it to purple because its "your blue is too close to France". Or going to green Italy and change it to pink Italy, since green ottos are too close, despite them being 2 really different tones of green, this literally sounds: "they are too similar and I have to spent 1 more second to noticed a diference".
C'mon, that's just being picky and silly.
If your excuse/reason/worry is because blue Portugal is "too close to France", I can present you around 5 different countries of how green Portugal is "too close to them" and other countries in a similar case. It's simply a really weak argument, since it's more than obvious Portugal would be using a really different shade of blue of France so you could tell the diference.
Once again, I will remind everyone here, blue Portugal is only for monarchist Portugal, not something permanent, since if the monarchy falls, Portugal would turn green.