I went with Yennefer on my first playthrough due to her and Geralt's past. At first I also found her too bitchy, she was entertaining to a degree but she could get on my nerves. But as you progress there's a lot more nuance to her character, especially towards the ending. A lot of it is just posturing anyway, she acts lovingly towards Ciri, respectful towards Emhyr, and tender towards Geralt (increasingly so if he romances her) . She isn't a Morrigan-esque character that can only act with contempt and sarcasm to everything and everyone crossing her path.
Most of her bitchy facade towards Geralt is her sense of humour, which is made clear in many scenes, it's part of their role play and he is happy to play along. You can find it annoying or humorous - I mostly find it humorous. Geralt will take control when it matters.
Maternal instinct and a sense of urgency also plays a part in her aloof and no-nonsense demeanor, as she seems to be the only character whom (mostly) shows consistency in taking the main quest seriously.
She isn't entirely sympathetic, but personality flaws makes interesting characters.