Where does "triple the survivability" come from?
I don't know about triple, but you can have the same AC without needing a pair of 16's to get there, you have probably 2 more hit points, and Second Wind has the potential to be a full heal at this level (and probably is, since nobody is going to wait until they are at 1 hit point to use it).
And yes, I'm aware two weapons isn't the best fighting style, but I was just responding to the statement that the Monk deals more damage than the Fighter at level 1. I'm not a maths guy, but it seems like Greatsword + Great Weapon Fighting isn't too far behind here (if you always rerolled anything below 3 the average would be 1 point less, but I have no idea how to map out "reroll a damage die of 1 or 2 but if it's 1 or 2 again keep it", lol) and you'd probably be better off taking another fighting style anyways.
Or you could take Archery with Heavy Crossbow at level 1 for 8.5 average damage and a potential +10% chance to hit* and stay safely out of melee- the Fighter has options while the Monk really doesn't.
*Your DM might actually remember soft cover is a thing, after all.
Now, directly comparing Monk to Fighter isn't really fair, the two classes are about different things. But the Fighter does get a much better deal at level 1 than the Monk, and is better equipped to deal with the rigors of melee combat.
For all the talk of Monk "skirmishing", you don't even start with the ability to disengage freely, you have less hit points, no defensive ability to speak of (other than saving 50 gp on armor), and when you do get defensive abilities, they are harshly limited and run on the same budget as some of your better offensive abilities.
Now it does get better than this eventually, but as the OP asks, I'm not sure how anyone can call the Monk "overtuned". It's a class that doesn't really excel at any one thing, that can feel resource-starved at low levels, and has a lot of situational abilities that are pretty neat when they come up, but don't always do so.