Bathroom help

My 5.5yo daughter used to have toileting down pretty well, but since late pre-k and much more since starting Kindergarten, has tons of accidents.

For some underlying context, she almost definitely has ADHD (major family history, and lots of signs at home) but because she performs well at school, they won't diagnose, even though the pediatrician sees it too. She also has a lot of sensory sensitivities and anxieties.

She won't use the school bathroom, and isn't having accidents there anymore, but the whole afternoon and evening are full of pee, poop, and meltdowns.

She's had so many UTIs, and no amount of trying to schedule potty breaks, help her stay clean, positive reinforcement, etc. has helped decrease the accidents, so the pediatrician recommended OT. We just had her evaluation, but of course all that takes time. We'd LOVE any tips or ideas now.

She's a great little lady, but we are so f-ing sick of cleaning especially the poop, and her defiant refusal to use the toilet. She's even said she doesn't feel it when she needs to go, but then insists she doesn't need to when we encourage it. She won't wear a pull-up during the day (still does at night, which doesn't bother me at this point).

We would greatly appreciate any help, commiseration, ideas, anything.