I have taken the same path you have. I worked with the Toast technical folks for nearly an entire month and nothing they suggested would work. Frankly, I grew very disgusted with their approach. Besides getting useless suggestions, they seemed unwilling to respond to what I would send back to them as a result of trying what they recommended. I provided detailed written descriptions and screen shots. But their response was simply more unhelpful suggestions. Eventually, since I was using Apple's Final Cut Pro X, I contacted their technical support and they helped me figure out how to burn Blu-ray Discs with chapter markers. The result is not as elegant as I had hoped with Toast but at least it works. It is really too bad that Apple discontinued IDVD as that truly worked in the past. I have found no other option that seems capable of replicating what I could do before with that application. Frankly, I think Corel should be called out for selling a product with functionality that neither works, nor can be "fixed" by their own technical people. I have posted reviews everywhere I can to alert consumers about this. And, of course, I requested and got my money back. But this comes after chewing up multiple Blu-ray Discs in the process of discovering that the Toast "experts" could not help me solve this problem. For what it is worth, I went through this exact situation in 2020 with Toast 18 and was told they would be issuing a new version that would work. Well, Toast 19 Pro arrived and we are in the same place. While I realize that a lot of the world has turned to media accessed in ways other than DVDs, there still is a need for this in many instances. If you happen to be using the same Apple application I am for video editing, let me know and I'll tell you what they did to help me burn blu-ray disks with chapter markers.