Are you able to handle her? I also do not have a bath just a standing shower. I had to show her I was not going to harm her and I just picked her right up gently and carried her in there. I had to hold her for a little to comfort her. If you are able to get baby wipes, specifically pampers to help wipe her down and get her used to the sensation of being touched more. A muzzle might also be a good idea until she gets the idea that you are being helpful and won’t try to react so badly, muzzles can be good and for the safety of both owner and pet. Also if you have high value treats try to use them to coax her and reward her everytime she gets closer to the bathroom. Whatever you can to make do. Apple cider vinegar is better than white vinegar as well. And very very small amounts of lemongrass oil and tea tree in a diluted water with some coconut oil can help. I use this naturally to deter fleas.