A brief look at the 2024 monk shows improved damage, a higher number of attacks than the warrior, a reaction to avoid/deflect attacks, and functional subclasses.

If your DM allows you to use ancient supplements, such as the TCE astral self, at higher levels you can have 6 attacks per turn and an AC of 22. If you take a level of ranger, you'll have the hunter's mark, so the optimized stat would be 6 attacks with the potential to deal 7d12 (1d12 per attack and 1 extra from the strengthened arms) +6d6 (from the hunter's mark) +30 (5 times 6 attribute bonuses).

This doesn't even include the stunning attack and the grappler feat, which would give you an advantage in grappling attacks.

While what you have said is true, it is also misleading. Hunter's Mark requires you to use your bonus action first to cast the spell, then again to transfer it to a new monster should your original target die. Against most monsters, you would be better off simply making more attacks rather than spending your bonus action casting/transferring Hunter's Mark. The only time it would be worth using the spell is if you are up against a single meaty target that will survive more than two rounds.

The 2024 improvements on the Monk can be very nice, especially with Deflect  attacks basically allowing the Monk to tank 1 attack per turn  that is even partially BPS damage, at the cost of their Reaction. I tend to consider it so useful that it often means I don't have Reaction available for anything else, such as Readied Attacks or Opportunity Attacks,  but I haven't yet seen foes take advantage of that.

That said, Way of the Astral Self is definitely designed with the 2014 Monk in mind, and would probably have quite a few things revised if an official update was published. The most obvious thing would be allowing Wisdom to be used to set Grappling / Shoving save DC.

There's also the fact that activating any of your Astral Self stuff eats your  Bonus Action, which is practically load-bearing on the 2024 Monk. So at 17 Monk / 1 Ranger you're spending 5 Ki/Focus points on your Bonus Action to be able to attack three times that first Turn. Then if you cast Hunter's Mark, it's another Turn with a maximum of 3 attacks. Only on the Third Turn are you fully On-line, and as Sequilonis mentions, if you're going for damage, you're almost certainly better off spending that Bonus Action Flurrying unless the combat is going to run long.