My belief is not without evidence. You have chosen not to believe the NT scriptures, but in them we have the words 'Eli, Eli, lama sabbachthani' spoken by Jesus from the cross, which are translated as, 'My God, my God, why hast thou forsaken me?'
Why would Jesus, in his dying moments choose to refer people to Psalm 22?
The wider context of the Psalms can also be seen as evidence. Psalm 22 tells us of a soul that relies on the LORD for life, as it says [verse 29] 'all they that go down to the dust shall bow before him: and none can keep alive his own soul'.
Psalm 23 tells us about resurrection. 'He restoreth my soul:'.
Psalm 24 tells us about ascension. 'Who shall ascend into the hill of the LORD?'
Then, we can begin to add other scriptures that tell us about the same events. Isaiah 53 speaks of 'him stricken, smitten of God, and afflicted'.
Zechariah 13:7, says, 'Awake, O sword, against my shepherd, and against the man that is my fellow, saith the LORD of hosts: smite the shepherd, and the sheep shall be scattered: and I will turn my hand upon the little ones'.
I could go on. But what evidence do you have to support the interpretation that Psalm 22 speaks about Esther?