It sounds like you have some ideas about who it might be and I would encourage you to trust your instincts about the cards! If it might help you lean one way or another about the deity in question, I’d be happy to throw in my two cents for your consideration- I know having some extra eyes on the cards can be helpful
(Using the card meanings from the Deity Tarot Spread on Spells8)
Card One - The Deity : Judgement
Judgement as the main card makes me think that this is a powerful, well-known deity (Major Arcana) who is associated with justice, karma, righteousness, law, and ethics.
Cards Two to Five - Traits and Characteristics : High Priestess, The Fool, The Magician, 7 of Swords
It is really interesting that you got the first three Major Arcana! This makes me think that this deity helps those at the start of their journeys- they are an initial advisor, guide, and assistant to someone who is starting their spiritual path.
The Seven of Wands is the “odd man out” of this bunch being the singular Minor Arcana card. My instinct is that their nature of going behind what is seen and dealing in deception and trickery may tie back into Judgement (the overall main card). The deity in question is likely one that assists with handing out judgement and being the hand of karma.
Cards Six and Seven - Sacred Symbols : Hermit, Queen of Wands
Since these cards are more about the symbols and signs associated with the deity, and the deck you are using (a very beautiful one!) portrays a minimalistic style, I’m going to draw on some of the images these cards depict in the Rider Waite deck.
The Hermit holds his lantern- a guiding light in the darkness. He walks with a walking stick.
The Queen of Wands is a mighty, proud woman who sits confidently upon her throne. She radiates authority and is associated with fire (wands). A black cat sits at her feet.
Card Eight - Personal Bond : Ace of Swords
As this is a personal card depicting the person’s unique tie to the deity, I’ll leave this one in your hands to best decipher!
All in all, I had two deities come to mind when looking at the cards:
Hekate - a popular deity of witches, known to hold the Keys of the Crossroads. She is a light in the darkness, a powerful female figure, and a keeper of justice. I can see Her in Judgement, The High Priestess, The Magician, 7 of Swords, Hermit, and Queen of Wands.
Brigid - Something about the Queen of Wands, a mighty female figure associated with fire, brought this Goddess of the Hearth to mind. The Hermit’s lantern also speaks to fire and about dealing with internal matters (such as those of the heart and home). Brigid is a deity who aids those in need and can act as the hand of justice
Again, just my two cents offered up to help you pinpoint the deity!
Wishing you and your sister all the best- blessed be!