to those who are getting the error containing;
"
Object reference not set to an instance of an object.
at Terraria.ModLoader.ItemLoader.SetDefaults(Item item, Boolean createModItem)
"
TLDR; re-enable mods until it loads properly.
with indirect assistance from Yoraiz0r and Sumenora, this is the information/workaround that worked for me; for whatever reason, sometimes when changing and/or updating mods, the items in the memory/off-hand slots will change to something random. (this happens randomly, i don't know exactly what triggers it.) if it is a mod item that is removed from an active mod, or the mod itself is inactive/removed, that item cannot generate. you need the correct item name from the correct mod for the memory slots to load correctly, even if it is an item that you have never manually put in one of those slots. due to this, it is a good item to occasionally back up your character, particularly the tplr file, with the memory/off-hand slots empty.
thanks to Yoraiz0r for the mod, its great for farming and especially mining.