For those experiencing poor economy, ya, I miss trading a bit, have you checked in the camp option and make sure to turn off the diplomacy economic changes? I found that businesses make a bit of money there. Having said that, it's not a lot of money, the return seems to be baked in at 20 weeks or so (4500 gets you around 220 per week) before you get a return, it's worse for the dye works. The secret is, don't buy them at all unless you are going to play that long. Generally I feel like I won around day 300, so it's worth it, the dye works is about 25 weeks. I buy whichever one makes sense, and hope it will payoff, but I don't buy them straight off, I prefer to take my first town first, which happens around day 60-80, so, I need my money to get set up, like hiring the Unsullied guy and generally like to buy good armor and an armored horse if I get unlucky with looting. Keep your party to companions if you can and get into fights and take all the loot for yourself, the don't care.
The problem I'm seeing with the economy has nothing to do with businesses, but the lack of positive trade deals for a starting character. With 7 points in Trade, I can barely ever find profitable merchandise to buy or sell, and when I do, one trade run taps it out. Funding a business isn't an option if you can barely even afford to feed your character with the pathetic trade earnings.
Basically, either you're a fighter, or there's no point in playing.
Well, I mostly command, so I get my army set up and let them fight, I sometimes go help trouble spots, like Caesar did. So, you make some money of looting, and tournies, that's how I funded my businesses. Still, I've gone back to 2.2, that's my favourite version of the mod.