Adraka means attained; root d-r-k.
Al-wuquf is a verbal noun and the object of adraka.
Ma bayna ... ila ... places the act within stated time limits.
Fa-qad adraka al-hajj gives the consequence: the central standing component of Hajj has been attained.
The grammar restricts the claim to attaining the standing; it does not say all remaining rites have been completed.