How do you prove that it’s in the child’s best interest to go from supervised to unsupervised with the non custodial parent?

Me and my ex are on very good terms. We currently have a modified decree stating my son can come and go freely with me for extended visitation as long as his grandma or grandpa are present on the same vicinity. Before the decree was modified we were also operating this way but then we simply Made it legal. I have months and months of texts showing how solid and healthy and good my relationship is with my son and my ex. I go above and beyond as far as reaching out and responding respectfully and kind in every situation. And giving all I can on the side that’s more than what my child support states that I must give. So my question, would it be fairly easy at this point to petition the court to try and modify from supervised to unsupervised without the agreed aide from the custodial parent? Seeing how there’s 2 plus years of solid evidence of the health of our relationship. Also, how easy would it be to go from supervised to unsupervised with the full support of the custodial parent?