Unsure if I should make my sister my maid of honour

I (27F) am getting married in 2026. I have one sister (23F). We are not close, we never hang out one on one. In fact we have a very strained relationship. She has a lot of mental health issues, she is very insecure about the fact that I am an engineer and she barely graduated high school. But I never talk about this in front of her. She has a very short temper and many dinners with my family end in her yelling and screaming and leaving.

The last few years I decided to not engage in fighting with her and only am nice to her. Pretty much my parents have taken the same stance since being around her is like walking on eggshells. My parents give her so so much and help her so much but she is so rude and ungrateful to them. I actually haven’t seen my sister in months even though she lives quite close because every week when we plan something as a family she says she doesn’t want to come.

So our relationship isn’t great, and we haven’t talked much about my wedding, but I think my family would probably expect her to be the made of honour since she’s my sister. My other 3 bridesmaids are going to be my friends from university and I would feel bad picking one of them to be the maid of honour since I am equally close with all of them. My sister is flat broke, and I can’t imagine her ever planning a bachelorette or even helping much on the wedding day. On the other hand, I feel like it might get awkward when family asks about who is my maid of honour and I say no one. Any advice??