Cultivation, realm, magic treasure, Dao artifact, martial equipment, these are the main components of a person's overall strength. Su Yi is currently in a state without a handy magic treasure, suitable cultivation techniques, or fitting special Dao techniques.
It's not that Liu Tangxi is withholding knowledge or unwilling to guide her, but rather, she doesn't have any suitable demon cultivation techniques at hand. If she blindly teaches something unsuitable, it could lead to issues.
So, on regular days, the only guidance she can offer is for the other person to learn some skills. However, Su Yi's skill tree is almost entirely focused on... support aspects.
Yes, she's a healer.
Her characteristic and element are both wood, primarily aiding others in healing and cultivation. She often actively snuggles into her husband's bed, circulating cultivation techniques to assist in his cultivation.