As you no-doubt know, there's a class of "best" grinders we loosely call Titan grinders. The most important feature these grinders bring to the table is consistency. That's the holy grail of espresso and without it you can't produce the best cup.
Beyond consistency, there's no such thing as the BEST Titan grinder because in the world of espresso, and coffee in general, one person's best is another's not-necessarily-so. Individual preferences for taste profile, operating mode (hopper vs single dosing) and workflow matter, and they vary a lot from one person to another.
Often when someone replies to the question you asked with that answer, the typical follow-up is, "Which one is better 'in the cup?'". The answer is the same: Individual preferences matter.
So let's start with operating mode. Much depends on whether you prefer single-dosing or hopper feed. And that depends on your coffee preferences and preferred daily workflow.
If you like to drink the same coffee most of the time, or for several days at a time, then a hopper feed makes some sense. The Mythos, K30, Peak, Compak R120, Compak K10 and EK43 are all great choices. As long as you keep a certain minimum level of beans in the hopper, it'll be consistent. If you do that, the only downside is retention: you'll have to purge 5g-10g of coffee at the start of a session or after a grind change. Evidently, the Peak retains quite a bit more than the K30, but reportedly the burr set is a bit more EK43-like when it comes to pulling light roasts. It's a tradeoff. Speaking of EK43, while many rave about this grinder, it's really a bulk grinder and reports are that the shots, while really good, don't taste at like traditional espresso.
If you change coffees a lot, a single dosing grinder is the way to go, and the hopper consistency and retention problems disappear. The Monolith Flat, Monolith Conical, EG-1 and Titus (or modified Versalab M3) are all excellent choices. There might be some very subtle differences in taste between the flat, conical and hybrid burrs, but again that's a personal preference item. You can't say one is generally better than the others, only that you might prefer the taste of one over the other.
Note that single-dosing grinders are designed for that purpose. Typically that means they have very low retention. You can operate any of the hopper-fed grinders in single-dosing mode without the hopper, but usually have to find a way to put a little weight on the beans and/or keep them from popping out of the grinder throat, and go through a purge routine to get rid of the retained grounds. This gets tedious and if not done properly may affect consistency and/or freshness.
FWIW, I own a Monolith Flat, which replaced a K10 operated in single-dosing mode that produced great espresso. The two grinders taste a little different, but both are first-rate. The differences are very subtle. I slightly prefer the Flat, but wouldn't be unhappy drinking K10 shots for the rest of my life. The measured extraction yields are nearly identical. The big difference is workflow: the Flat is hands-down much faster, easier, cleaner and has virtually no retention. The K10 required a "bump-and-grind" routine that got very old. The Flat takes up much less counter space, too.
There's a current trend toward "unimodal" grinders, based on the theory uniform particle size produces more even extractions. But it's far more complicated than that. For example, while excessive fines are bad, you need some fines for proper espresso flow rate. The scientific jury is still out on all this, so I wouldn't base a Titan grinder decision on claims of unimodality. Taste is what matters.
Incidentally, many would consider your Mazzer Major a Titan grinder. The flat burrs are quite large, comparing favorably with all of the hopper-fed grinders mentioned above. I would bet that operated properly the taste of espresso ground on your Mazzer Major is very close to any grinder I've mentioned. Workflow is another matter.
The bottom line is, if you really want to make an informed decision you have to operate each grinder and taste the cups they produce.