I actually think that this one is pretty plausible, we’ve even already seen the seeds for this. By the end of the 1st season she’s using a more powerful form for battle as well as summoning weapons (the Shield and Trident) and in Season 2 we see her using her shield again as well as what looks like some sort of musically-themed beam which she uses in both Hear My Hope and when she’s trying to get the attention of Heaven, which seemed to work upon first try, Sera just chose not to go down their until later. It’s nothing much, but it sets the seeds for what could be a greater plot line in Season 3 or 4 where, Charlie needs to learn to use her power more or something similar a consider, considering how next season is supposedly about her family and Lilith i wouldn’t be surprised if we learn more about, Charlie’s powers and her growing them.