How to get more profitable trades / use my trade capacity?

So I have been playing holland into the Netherlands. Verry close to the age of exploration and in control of the coln (now Keulen) market. I make a decent 24 ducats a month with stability investments at 0%.

Now I was thinking the Netherlands would be quite good at trade with its great ports and valuable industry but when automating the trade its only using about 10 of my 50 trade capacity. From what I understand this is because all of the "profitable trades" come with a sizable upkeep kost of half a ducat per trade capacity. Then again what's shown in the trading tab seemingly already includes the maintenance fee based on the costs and profits when hovering the final profit.

Could anyone explain to me why these trades are not picked by the trade AI, and if it all does make sense how I could create more profitable trade opportunities? Kind of want to start using more than 10 cap especially when seeing AI England and France using almost all their cap, that being 40 and 80 trade cap respectively. Seems like I'm doing something wrong. Surely they don't just dominate all European production making their products dirt cheap in other markets.