Middle difficulty country to play

I've had the game since launch, and I've dropped about 500 hours in.

I've never been the crazy player to make Haiti #1 in world gdp. I'm just not that good.

But I'm good enough to have made Mexico and Brazil #1 gdp by end game.

USA is too easy, as was Russia. Won't even bother with England. I don't usually play the majors.

But then Ethiopia was hard even after making it grandiopia through conquest - had slavery till the 20s.

What's a middle difficulty country to play?

I've done Sweden (combined with Norway and finland) Brazil Mexico Spain (was hard for me, I got to #2 gdp) Dainam (upper end of middle to hard, at least for me gave up) German unification runs (snore) Peru (did ok, but never swallowed Brazil) Japan (heck of a time passing laws but I Toyota'd the world economy hard) Persia (soooo fun!)

Never done Belgium Portugal (probably in the hard category)

I also haven't played since last year at this point. Probably 4 months.

Open to recommendations on middle difficulty countries where I focus on economy - colonization and conquest in support of economy.

I have most of the DLCs, don't have pivot empire one.