I would suggest using the Meteonook tool to find your weather seed. It doesn't tell you exactly when she'll be there, but it'll reveal your fine and heavy meteor shower days, which will give you an idea as to when to expect her.
Also, I used Turnip Exchange to visit Celeste every day until I had all the recipes (minus zodiac). If you're in a hurry to get them all, that would be my suggestion.
Yikes. At first she appeared fairly regularly but it’s been a while now. It might be worth seeking her out on other islands if there’s that many DIYs...
good thing she doesn't give repeats but yeah, i don't want to get another wand from her. i've had enough of the regular wands and i don't even use them anymore. the excitement wore out from where the wands in game was new lol.