Is a doula really beneficial for an unmedicated birth?

Several months ago, I contacted dozens of doulas in my area and only one responded. We emailed back and forth for a few weeks and we were supposed to meet up today to talk about her services. She forgot, and she wasn't even good about responding through email either. I'm already seven months pregnant, so I don't want to spend the next two months wondering if she'll even show up when I'm in labor. I want a water birth and I haven't had great experiences with the staff at the hospital, so I would like someone there to be the middle man. I don't want to have to keep reminding them that I'm not going to push when they tell me to push or if they're rude, I don't want to have to even talk to them. (ETA: I just realized this sounds like I just don't want to talk to the nurses. I didn't mean that. I'm only saying that I don't want to talk to them if they're rude.) And the ultrasound tech and receptionists were rude, so I'm just mentally preparing for that. My husband will be the only family/friend in there with me but he speaks Spanish, so he won't be able to be my advocate.

That's really the only reason I was interested in a doula. I don't feel like I need any help before labor. I just don't want to be too distracted while I'm focusing on breathing exercises and listening to my body. But if you've had a natural birth before, is it really that big of a deal? And do hospital staff generally listen to what you want or try to tell you what to do?