My Ds3 had a fear of toilets around that age. I can't remember what we did but eventually he started using them. He won't flush them though even now and he is 6. Can you take a potty to day care for her? Hopefully they will allow that

Maybe ask her why she is scared of other toilets . It could be because its just simply different. If you aren't bothered by her wetting her pull ups then I wouldn't stress about it. Or maybe not use the pull ups for a short shopping trip and see if she realises she has no option but to use the toilets available kwim?