Personally my favorite right now is Venefica. "World's most powerful witch who could probably take out entire kingdoms but actually just wants to run a cute confectionary shop but the other witches keep committing evil in her name even though she never asked for it" is an AMAZING plot for a character. Also her design is *chef's kiss* and has everything I love: pink hair, tan skin, voluptuous yet fit, and a fun Castlevania-style gothic "witch of cinder" esthetic
Also I have a crippling mommy fetish so that adds points; and making lovers/wives out of super powerful goddess-status women in games like these is very satisfying to me
However, when Perpetua gets expanded upon and maybe opens up to us a little more in the future, I personally feel like she could EASILY be a top contender for best girl. I have a soft spot for Megumin/Fischl-type characters like her that seem like they just want friends, and having a slime girl that isn't the ditz stereotype is also a major plus. ALSO I have a conspiracy theory that she either IS the Demon Queen or is related to her; perhaps a daughter or niece. I don't remember who said it but one of the girls mentioned a rumor that the Demon Queen was actually a slime, and as an avid fan of 'That Time I Got Reincarnated as a Slime', a twist like this would be incredible because slimes often get dismissed as non-threatening creatures