Fender...you ae doing a great job. So often, we bend over backward to make sure they get to spend time with the other parent...we change plans...we offer up other times...
Your daughter deserves the best. She deserves to see her grandparents. My thought is your ex might not have taken off time anyway and then she would have missed that trip.
We can't make then love their children. We can't make them be parents. We can just b the best parents we can be. We try to teach our children to set boundaries but so often I see people here flip stuff around so the errant ex can spend 5 mins with them.