This is just stupid...I want to steal a horse and keep it from returning to where it came from...I have convenient horses, and it does resolve alot of the annoying problems with horses....except this one

i dont know about any mod but you can try using console commands on horse setownership and adding horse to playerHorsefaction that could work.

Immersive Horses has that feature, but you would have to choose between it and Convenient Horses.

Immesive Horses or open the console click and type

setownership

on them. Not sure if it makes spawned horses persistent though.

they will still have their old AI and will wander off to their place of origin that command alone wont be helpful you also need another command to make them follow you.

I found a mod that allows me to keep stolen horses...convenient horse herding....all I had to do was type setownership into the console....I stole a horse from a Stormcloak camp and he's still with me, lol.