I like the idea of selling high-tech weapons on to another world, but MC's issues with his parents, romance, systems with attitude, and getting involved with random shit and cultivation just bothered me the most. This would be great without involving cultivation and romance. Just pure selling weapons, developing weapons from muskets, flint locks to missiles, just pure destruction, killing, plotting, and no family shit or romance would be very great instead. Have you seen the War Dogs or Lord of War movies by nicolas cage? or even anime like jormungand and black lagoon anime? those would be great references for this novel.