Heya,
Thanks for the updates re: flexgrow. Being completely ignorant, I wasn’t sure how to implement the code that was discussed.
However, after reqatching the vids, understanding things a little better and doing a tad bit of research, I updated my code from the lecture to be:
VisualTreeAsset original = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>(path + "TaskListEditor.uxml");
TemplateContainer templateContainer = original.Instantiate();
templateContainer.style.flexGrow = 1f;
container.Add(templateContainer);