Since you're getting it at 5th level, you could burn 2 ki for 6 attacks in a round (2x Flurry of Blows). You could Flurry and Dodge/Dash/Disengage.
Shadow monks could use their shadow step twice and get 2x advantage attacks by spreading their extra attack around.
Sun Soul monks could use burning hands twice in one round or attack, flurry, and burning hands.
That's pretty much the extent of it without mutliclassing.
With multiclassing you get into some weird stuff where a Fighter/Monk/Sorcerer (hella MAD I know), could then potentially cast four spells in a round as long as three were cantrips and 1 quickened or with Action Surge, two standard action spells plus then two bonus action features like say... burning hands as a Sun Soul monk.
That combo could, once or more times per combat at higher levels have a turn with 2 standard actions, 2 bonus actions, and a reaction. Action economy is destroyed at that point.
I don't know if it's "way" overpowered, but it is a big boost in power since action economy is really the crux of combat.