I wouldn't say glass cannon either.
Spending ki for a bonus action to use dodge in addition to attacks is nice, as long as the ki is available. It's not really tanking but it's definitely good for short term. They are competitive in damage with some falling behind -5/+10 use on a couple of feats but those don't hzve high AC either having given up shields. They fit more into the skirmisher style with the speed and ability score focuses that have good skill / ability check synergy. Additional class features capitalize on that skirmisher concept, like stunning, for a class that can move far fast to pick out prime targets for such effects.
AC is moderate and going a bit MAD does get to 20 but slacking on one or two points still leaves a similar AC to most classes that aren't using shields. Evasion, deflect missiles, stillness of mind, purity of body, diamond soul, and especially empty body reinforce that lack of glass cannon because there are more defenses to consider than just AC, although the moderate AC plus dodge or invisibility is still pretty decent. Empty body is generally disadvantage on attacks against you and resistance to all damage but force so it's pretty good. A person could go elemental monk for eternal mountain defense earlier and doesn't have material component costs when monks gain CON save proficiency (all save proficiencies) and can spend ki to reroll it if failed.
I wasn't really a fan of elemental monks. I didn't think the elemental spell selection had enough options and spent ki pretty quickly using them. Shadow monk has nice stealth abilities and opportunist can be an easy bonus attack but my personal preference was with rogues. I really enjoyed open hand monks.
Spending ki for an extra attack is pretty good very early, but spending ki for an extra attack with a free knock down, push, or reaction denial ability is better. Reactions prevent opportunity attacks as part of the skirmisher concept to avoid being attacks or needed to disengage. Knockdown improves accuracy with advantage on following attacks until the target stands up for increased damage potential. Push has the same effect as reaction denial unless there's an environmental factor, usually, but push and knockdown allow for saves while reaction denial does not. Wholeness of body equals a daily bonus healing ability that isn't bad but useful in a pinch. Tranquility has a ton of flavor. Quivering palm is great because it's a cheap save or die effect in an edition where save or die effects have become almost completely non-existent and it can be done several times per short rest.
In my experience, open hand works if you want to play a monk and you are looking for a melee character. He can escape easily enough, if needed, and is strong defensively in ways the fighter or barbarian are not. Tough and mobile might be good feats for you with a heavy focus on WIS and DEX in your ASI's. When I was testing monks, I used human variant, point buy, and ignored STR, INT, and CHA. Between step of the wind and unarmored movement and the mobile feat I could melee kite, and using open hand technique to knock targets down meant they didn't have enough movement to get to party members staying far enough from combat; I didn't need to push or deny reaction to prevent opportunity attack because of the mobile feat.
They can be a bit behind damage builds and/or a bit behind AC builds but they do enough different things that they can do well enough for short term. You might watch your tactics to either keep combats short or use a fair bit of crowd control. Longer combats and lack of short rests can be big issues because without ki they can lose a lot. CC reduces the need to spend ki.
As with many things; that is subjective personal experience.
