Idea 3

Honestly I am surprised that theirs not a lot of solo leveling or tensei slime fics.so this is what I came up with .

1 an oc is reincarnated in naruto and his cheat is to turn into a slime and has rimurus great sage and gluttony

2. an mc is transmigrated into solo leveling with the same powers above

3 an mc who's a mage (solo leveling)he can even become the monarch of magic