Some things to note:
• The new Hybrid legendary module can be equipped with a magical or physical character type. So let's say you are playing Eunha. She's magical so you would get a hybrid mod because of the magical Stat on it. You will replace one of your previous modules with it. If you're a hybrid character like Lucy, you would literally use all three modules... that's definitely not cheap - But please do note: This is considered minmaxing so it is completely optional and not necessary
• The legendary modules drop in all three dungeons (glidal, xue & triss) the fastest one to do is the glidal one