For example if u have a full set the achivement comes at 4:30....or rlly close to that
Is it that time for all sets, cucumbers, etc to get achivement?
or it happens twice a day or multiple times a day?

the archievment come exactly after 24 hours

I believe they come at 12am GMT

It takes 24 hours for the achievement to arrive

I know for a fact that it dosen't

Everything On the achievements page updates every 24 hours.

Depends on the achievement.
Many are broken or based on weird circumstances.