“And the angel answering said unto him, I am Gabriel, that stand in the presence of God; and am sent to speak unto thee, and to shew thee these glad tidings.” Luke 1:19
Since angels are sent by God, we can surely thank them for doing their duty (as opposed to the angels who didn’t - ref. the Epistle of Jude).
What is your point? I am confused as to what you are saying. Are you trying to equate thankfulness with worship?