Overused Pet Names
Currently writing a story that draws heavy inspiration from Roman Catholic lore, but twisted into a horror/fantasy setting. For the longest time, I had this vision that I'd like my MMC to have his pet name for the FMC be "Angel" (it holds endearing and plot-point value), but now I'm feeling like that might be overused (i.e. The Woven Kingdom, All Rhodes Lead Here, etc). I have thought about ripping the Band-Aid and continuing with that pet name, but should I just move on to something else? It gets muddy in my head when I think about using names/tropes that are important to me from a religious perspective (like the name Cain and Abel) but just happen to be overused by writers. I was also considering something like "lamb". What's most important to me is the weight a name (or nickname) like my FMC's could hold for Catholics.
Context:
FMC is born into a crime syndicate family. Grows up, learns the trade, gains the nickname "The Angel of (Syndicate Name)." Later, she is recruited into a team of elite soldiers who are tasked with "handling the demons that are plaguing the world". MMC begins to call the FMC "Angel" in a derogatory manner, but later in an endearing manner.