Psalm 69 goes right on talking about Jesus toward the end of the pslam, although we saw early that this psalm is also about David.

So what was the Christ to drink?

When the death sentence had been given, all the soldiers had gathered around Him. They stripped Him and put a scarlet robe on Him, and crowned Him with a crown of thorns, and mocked the King of Heaven and Earth, and spit on him, an beat Him about the head. Then they took Him to the place of execution. Psalm 69 says,

“They also gave me gall for my food.
In my thirst, they gave me vinegar to drink.”
Psa 69:21.

And that is how it happened. Matthew says,

“They gave him sour wine to drink mixed with gall. When he had tasted it, he would not drink.”
Mtt 27:34.

Mark says they tried to give him wine mixed with myrrh, Mk 15:23. Evidently these concoctions were intended to dull the pain. John records that a jar of vinegar/sour wine was standing there, and when He said He was thirsty, He was offered some on a sponge.

“When Jesus therefore had received the vinegar, he said, “It is finished.” He bowed his head, and gave up his spirit.”
Jn 19:30

We can see that this also fit Him. And what then of those who plotted His death? The death of the “one and only son” of God, Jn 3:16?

May their food even be a snare a to them.

It is obvious that bad things can become a snare and a trap for us. Less obvious is it that sometimes even good things can be a snare to us. Such men deserve deserve the very worst, so it says

“Let their table before them become a snare.
May it become a retribution and a trap.” Psa 69:22.

Then it says,

“Let their eyes be darkened, so that they can’t see.
Let their backs be continually bent.” Psa 69:23

Paul quotes these verses of the Jews under a curse
for rejecting their own Messiah, Rom 11:9

This is speaking of Jews who rejected the “one and only Son” of God, for,

“11 He came to his own, and those who were his own didn’t receive him. 12 But as many as received him, to them he gave the right to become God’s children, to those who believe in his name:”
Jn 1:11-12

And here again, Paul like the author of Hebrews quotes this psalm as being of David, Rom 11:9.

God sometimes pours a spirit of sleep over people,

Sometimes they don’t deserve to know what will deliver them. Isaiah says that of the Jews.

“For Yahweh has poured out on you the spirit of deep sleep, and has closed your eyes, the prophets; and your heads, the seers, has he covered.”
Isa 29:10

Paul also quotes this of the Jews in the context of rejecting their own Christ, Rom 11:8.

Is this failure of the Jews permanent?

Paul says no, in Rom 11:11-12, and that is a grand subject, but not until later in Psalm 69.

Scriptures are from the World English Bible (WEB), a copyright free revision
of the original ASV American Standard Version 1901