1For the conductor, on the ayeleth hashachar, a song of David.
This means the person speaking is David. Any I or me refers to David.
2My God, my God, why have You forsaken me? [You are] far from my salvation [and] from the words of my moaning.
This is David expressing his despair as he is hunted down. It doesn't mean God has actually forsaken him, but it does mean that it felt that way to him.
3My God, I call out by day and You do not reply, and at night I do not keep silent. גאֱלֹהַ֗י אֶקְרָ֣א י֖וֹמָם וְלֹ֣א תַֽעֲנֶ֑ה וְ֜לַ֗יְלָה וְֽלֹא־דֽוּמִיָּ֥ה לִֽי:
4But You are holy; You await the praises of Israel.
The word YOU follows the word GOD, and therefore refers to God. Not the messiah.
17For dogs have surrounded me; a band of evildoers has encompassed me, like a lion, my hands and feet.
As you can see, this translation from the HEBREW is superior than the translation from the Greek Septuagint that Christian Bibles use. Again, it is David describing his condition, not a messianic prophecy.
19They share my garments among themselves and cast lots for my raiment.
Here David is describing something that happened to him. It is not a messianic prophecy.
You get the idea.