Here are the verses in Hebrews that indicate that Christ was, indeed, struggling with striving against the death on the cross ...
Hbr 12:1 Wherefore seeing we also are compassed about with so great a cloud of witnesses, let us lay aside every weight, and the sin which doth so easily beset [us], and let us run with patience the race that is set before us,
Hbr 12:2 Looking unto Jesus the author and finisher of [our] faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God.
Hbr 12:3 For consider him that endured such contradiction of sinners against himself, lest ye be wearied and faint in your minds.
Hbr 12:4 Ye have not yet resisted unto blood, striving against sin.
I appreciate those verses but don’t feel they make a compelling case that this was the source of distress at that particular time. Didn’t the Lord upbraid Peter for seeking what expositors say our Lord would be seeking. Too much inconsistency - imho -here for our Lord who was fully determined to go to the cross.