If it helps my nearly 3 year old cracked it in 2 days just this week.
I put a few days holiday in when we started potty training and luckily my son picked it up quite quickly. On day 3 we were on 0 accidents
I booked a few days off work and within a week my daughter was dry. Similar to @Hayley we did naked from the waist down for 3 days then added in knickers and dresses after that.
We did it over xmas, 3 days naked waist down, then trousers without pants until successful with that then add pants. If you can’t take time off do it over the weekend then at home at least until they’ve got it. But longer you used nappies at childcare the more confusing it is for them and it takes longer so better to go all pants I would say. Good luck!