It is not a feat it is a fighting style (which can be gained through a feat), but a Monk can get that too or take a dip in fighter and get it.And not to mention Tasha's guide made it worse, because now you can start at a d6... or a d8 if you are using no armor or a shield? WTF?!? A Monk has to wait until Level 5 to do a d6, and Level 11 to do a d8... Yet, any old Sloppy Joe can do a d8 with their fists if they take the feat from Tasha's (I forget its name).
For me what makes the Monk are the subclass abilities (some of which are good and some aren't), movement, stunning strike and free bonus action attacks. I think taken as a whole these things bring the class up to be comparable with most other classes (provided you take a good subclass).
What I really want to do is combine a Kensei Monk with a bladesinger. That would be pretty awesome I think, rocking a dex-based warhammer or longsword booming blade with bladesinger extra attack and then a bonus action martial arts attack on top of that. You can have a screaming high AC, awesome movement and deal awsome damage without using any ki. Start with a 15 intelligence and pick up fey touched and hex for even more damage. It would take 10 levels to really come fully online though, 11 if you want stunning strike.
I had one I started playing, she died at 2nd level though (level 1 wizard, level 1 Monk) when she rolled a 1 on a death save and then took another hit while down.