I am unable to replicate this. It seems that you're making a number of changes to the tutorial's code, and have introduced a bug or memory corruption along the way. None of those errors in the stacktrace are coming from the tutorial code, so it doesn't appear to be at fault here.
You seem quite keen to localise this game into another language, but I would suggest that if you want to learn how to support fonts with glyphs that include Chinese, Korean, Japanese, etc. that you opt for something a lot more simple than the larger projects here. There are a lot of moving parts in SDL2 Shooter 3 that could break while you're doing this, which will only lead to a lot of frustration.