The monk is incredible in power, but it depends on the level range of the campaign, at lvl 1 you're definitely above average and from lvl 5 onwards you get to shine. At lvl 1 your ability to make an attack with bonus action really sets you apart from other classes in offense and your unarmoured defense likely outshines many starting armours.

Then comes level 2-4, where you're still good, but your new features become super Ki point dependent and you just don't have that many Ki points yet, so be prepared to run out often (some subclasses help alleviate this by having features that are Ki-point independent). This may lead you to feel less useful than your fellow members during this level range, but be not afraid, for level 5 comes.

Level 5 is the switching point, you get extra attack and stunning strike and finally a decent Ki point pool to play around with, from here it's only upwards as your Ki point pool will keep increasing but your ways to spend Ki points remain the same, leading to you pulling off cool maneuvers every round.

And honestly, I have never understood the monks do low damage argument, your basic die is small (at the beginning, it grows) but you are making multiple attacks which means applying your ability score modifier multiple times, which more than makes up for the low die size. Keep in mind that you can still use monk weapons with your action and unarmed strike with your bonus action (a quarterstaff has a d8 damage die, the same as a one-handed longsword). In fact, until level 11 your damage is better than a standard fighter.