Surprised no one has Simple Tab Groups. Maybe the Tree Style Tabs ecosystem is more popular, I haven’t tried it. It’s just a 2-level hierarchy instead of a tree, but it serves me well. I have one tab group for each class I have at university, plus some other ones for interests like lean 4 or minecraft, and two for other compulsory online services like banking and travel planning. The Add-On combines saving the hassle of reopening tabs with reducing the work looking through the open ones.