I've played Clerics and Warlocks at low level and using a Spell Slot can have a WAY bigger impact than spending a single Ki point. If you drop Sleep on the right group of enemies, or drop a Bless on your team mates or a Shield of Faith, it has way more of an impact than bloody Patient Defense.
Of course a sleep spell has a higher impact. Noone denies that. But those are different kind of resources. Clerics only have a few spell slots per day. And channel divinity of course, warlocks use their spell slots often for hex, which can end very fast. Monks at low levels have quite some offense without spending ki at all. Quarterstaff + unarmed strike + high mobility is not bad.
It is just, that as many have identified, the way D&D is played, short rest resources are less impactful than originally intended. And MADness of the monk is a bit of a problem.
But now, compare the monk level 2 to a rogue. Yes, the rogue has cunning action, but if they want to deal as much damage as the monk, they need to spend their bonus action on an off-hand attack. 3d6+3 damage (rogue) vs 1d8+1d4+6 damage (monk). Of course, taking hit probabilities into account, the rogue is slightly ahead (1d6 applied t nthe first hit) , but then you also need to account that this damage is conditional.
Then compare monk hp to rogue hp (same), and AC (both probably 15) and you see that on paper both classes are rather balanced against each other in combat. It just that because the monk needs to spend resources for things the rogue can do at will, that it feels worse. Then top it out with expertise for the rogue out of combat and suddenly it feels that the monk should get a little bit more either out of combat or in it.
Ok, that was longer than intended. So TLDR: monk is in a better shape than theory crafters make us believe, at least if you play closer to the assumed adventuring day.