I dunno wtf the calculations are for probability of getting a fief in bannerlord. I got Gaos castle when I initially joined up w/ the Southern Empire, went campaigning for a bit, about a month or two later Lycaron was taken, and I participated in the army which retook it. I then got Lycaron for some unknown reason. This is wack as hell.
Also, fiefs pale in comparison to caravans when it comes to making money. Each caravan is making me 1k+ gold per day, and that's without the wages perk from trade (I thought workshops would be better but they got capped to 200 :c). Workshops can also be a fast source of income, just leave one running for a while and it'll build up some insane capital (I've left a pottery shop running for a month and I can already sell it for 18k, not to mention the 200 gold a day is nice).