For me personally It's the wrist, Every time I try doing something cool It just falls off when It gets minimal damage and make me lose. It's been the main reason why I've been losing so much lately, It's like my wrists are made out of weak plastic made in China.

Well it may not be that they are the weakest joint, but rather they take the most strain. eg, in judo and aikido they usually have to resist the inertia of a whole other tori, and since they are farthest from the Chest joint the moment is really quite large

Weakest - neck, strongest - ankles. At least from my experience.

In my opinion, are the pecs and hips/glutes. The strongest are the ankles, indeed.

weakest - neck: mostly because you have some space to glitch through wish make it so easy to dm.
strongest - ankles: they are small and doesn't have alot of space to glitch through so its hard af to dm it(except when using grab ofc).

well wrists are weak but they come after neck,knees and abs imo. they get dmed because of the pressure from the full extending when you hit with them and because of the tori's weight if they dm on the ground
anyway it can be fixed by relaxing,holding and contracting them.

I'll agree with sloth here. Every joint has the same dismember threshold, but it is way more common to dm an wrist because of the pressure applied to it - you get the momentum and hit your hand against the inertia of the other player. Ankles are harder to dm because of the lack of said momentum with kicks etc (depends on the way you play), also the flat format of the feet, imo

I would have to say the pec and in second the wrist because those 2 joints dismember the most in my opinion, the ankle is also quiet weak but we just dont use it in a way to dismember, like in parkour with dismember on makes it possible to dismember easy like ones wrist.

neck is probs the most useless. I usually just keep it extended or relaxed. Changing it barely effects your moves. I'm not sure what is the most important joint since you need to use them all in unison, not including the neck. I could keep my neck held the whole game and it wouldent effect much.

Weakest - Neck (unless you saved yourself from decapitation

Strongest Ankles (I have my reasons )

ok i dont think we need to talk about this anymore
and a tl'dr of all the posts above:
every joint have the same dm hold but the defficulty of dming it depend on how much space between body parts you can glitch through and the way it get used wich decide the amount of force applied on the joint.