I find that the best all-round lens never existed, and never will. It will always be too expensive, not wide enough, too heavy, not enough bokeh… and so on.
Professionally, my Canon EF 16–35 ƒ/2.8L covers 95% of my clients’ need. Personally, my Canon EF 50 ƒ/1.4 helped me captured 99% of my personal best shots. And rarely, my old-school EF 80-200 ƒ/2.8L would kick in and took some of those impossibly gorgeous images.
So the variable changes all the time. My suggestion is for you to sit back and have a good look at your images; discover what is it that you are really good at, and what kind of photography gives you the most satisfaction, only then you can prioritize which lens to get first, and draw an imaginary roadmap to give you a longer — if not non time-limited — satisfaction.