This datapack simply use wandering trader.
To make the wandering trader follows you, tag yourself "target" and use /function path:reset_all to reset ALL
To summon the path finder use /function path:summon_path_finder
To summon the target use /function path:summon_target
Important:
The wandering trader won't be invisible, so you can make a resource pack to change the model and texture of the wandering trader
(PS: Give credit to me too!)