The first link you provided is a homebrew (non-official) class named artificer.
The official artificer (published in Tasha's Cauldron of Everything, Wayfinder's Guide to Eberron,Tasha's Cauldron of Everything and Eberron: Rising from the Last WarEberron: Rising from the Last War) regains their spell slots after a long rest.:
To cast one of your artificer spells of 1st level or higher, you must expend a slot of the spell’s level or higher. You regain all expended spell slots when you finish a long rest.
-E:RftLW pp. 55-56, TCoE pg. 11