My eldest has never been a fan of washing so I create reasons for its necessity because she's super logical but also literal. She loves to paint, play with goop, jump in the mud so we just do something messy everyday and then I can just say well you need one right and it seems to work because she can actually see what needs washing. I know there is stuff that needs washing even when you can't see it but it made no sense to her, she didn't look or feel dirty so why does she need a wash? So this just made it more visually understandable for her.

I hate washing too if I'm honest. It's a sensory thing for both her and I so having a reason for enduring it helped. We also have distracting things for playing with during and we make it as quick as possible. We only wash hair maybe once every week unless we get something in there (which actually can happen pretty often around here) and we do trades so I do hers and she does mine which helps her feel more comfortable as she can understand the mechanics of what will happen from being on the otherside.