To complete the achievements, you need to collect 900 pieces of each of the four ingredients (you need to do all 4 repeatable locations 45 times).
Have you played the 4 locations that many times?
What level are you at in the achievement?
For example, if you collect 20 dew, do you see a change in the achievement (for example, it shows 260/300 instead of 240/300)
Serving guests is part of the quest. Did you give the guests the potion they requested, but didn't get the reward for the quest?
Please upload a screenshot of what you think.
Or contact Pixel Support, they can see your game and if you have a problem they can help.
⏳ Look out for the event to end on Tuesday.