Both feasts point to (and promise) Christ's eventual death on the cross.
Which occurred in the fullness of time, so the temporal and earthly timing of the various feasts and rituals established by Moses are irrelevant, for they all point in purpose, to the same Person and one-time Event that was fulfilled in the sacrificial Incarnation of Jesus Christ.
Should I conclude from your statement that the Pentecost event of Acts 2 had no relevance to the Lord's instructions regarding Israel's appointed times which He commanded through Moses?
What does 'fully come' mean?
Act 2:1 And when the day of Pentecost was fully come, they were all with one accord in one place
Could the event have taken place at any time and at any place?