@Kirsty Bunning she has a comforter already! How long did it take for yours to be ok without a dummy??
Probably 4 nights to be completely fine. We didn't do any other sleep training/self settling things with her then. Just sat with her lying in the cot while she settled and went to sleep, and then fed her when she woke in the night, although not fed to sleep. I've seen some people cutting a V out of the dummy so the baby doesn't enjoy it as much, or you might be able to find some gradual dummy weaning approaches that help.
Could you try and introduce a comforter for week, alongside the dummy, and then go cold turkey again? We had a comforter and went cold turkey at 6 months but maybe my LO wasn't as attached as yours. It's tough but I think it's worth it 🙏