Totally understand where you're coming from, OP! NH is my first AC game, and the online factor is definitely a bit intimidating. As such, I've taken it very slow and simple with any trading, and I've barely hosted at all. Thankfully I've only had positive experiences so far, but I only use Bell Tree and the 25+ Tortimer's discord for trading, both of which seem to be very warm and un-predatory communities.
My advice would be to not jump at the first chance to pursue something you might be after, but wait for posts from people who seem like they're doing it for fun and magnanimity instead of making a quick buck. Good luck!
My advice would be to not jump at the first chance to pursue something you might be after, but wait for posts from people who seem like they're doing it for fun and magnanimity instead of making a quick buck. Good luck!