I'm underwhelmed and disappointed by the changes to the base class.

However, the monk actually works fairly well as a hit and run skirmisher now without having to rely on the Mobile feat or sacrificing damage with patient defense or step of the wind, thanks to the subclass abilities.
Shadow can rely on Darkness to move away without getting hit. Elements gets reach. Open Hand got shafted, since Addle rely on saves to be able to safely move away.

Monks still have too few Dicipline points until around level 7-8.

Monks are still very MAD. They need Dex, Wis, Con. Add in Str if they want to grapple.

Increased martial arts die is a good change. Too bad it no longer applies to weapons.

Access to mastery is "alright". Vex is probably the best option. I don't think the other options available to monks are very useful, unless the monk gets access to two weapon fighting style for Nick. The fact that monks can't apply mastery to their unarmed strikes is a huge missed opportunity imo.

Stunning strike nerf was needed, but maybe they nerfed it too hard. It used to last until the end of the monks next turn, now it lasts until the start of the monks next turn. Maybe limiting the attmepts to once per turn is enough?

Hightened metabolism is ok. But it's weird how they attempt to get rid of and solve short rest mechanics when a easier fix would just be to shorten short rests. When you get access to this, the Dicipline point problem is mostly over anyway.

Self restoration as a bonus action instead of a action is alright, even if it's pushed back to level 10. Better hope you can still use your bonus action when subjected to those conditions. Why not make it a reaction when subjected to those conditions? And why did monks lose their immunity to poison? I loved that.

What would I change? I'm not sure but here are some suggestions. They are probably not balanced.

Sever the ties to "east asian" monks completely and remove reliance on WIS.
Monk Save DC should be based on Dex, Unarmed defense should be 10 + Dex + Con, Monks are no longer MAD. I don't think this will happen, but it will solve a lot of issues IMO.
More Dicipline points in the early levels. They should start with at least 4 at level 2.
Allow Monks to use their Dex for Jumps and Grapples.
Martial arts die should also apply to weapons. Monks should be able to apply some of the masteries to their unarmed attacks.
Stunning strike. Since Stun is too good, rename the feature and have it apply another condition, like Daze or Incapacitated. Maybe make it only cost Dicipline if the effect actually works.
Hightened metabolism. Since they refuse to shorten short rests to like 10-15 min, make this usable twice between long rests.
Self-Restoration. Make it a reaction when subjected to the conditions. Maybe add a Dicipline cost.
Give back poison immunity.
Open Hand Technique should be able to be used with all unarmed strikes, not just from flurry of blows. Addle should not require a save.