Mais ou menos is everyday Portuguese for so-so, and this drawn out version became a shareable reaction clip in Brazil through its association with Panico, the long running comedy programme known for catchphrases and street sketches. Clips repeating a short answer like this spread easily on soundboards and messaging apps because everyone understands the meaning even without context. It remains popular for low stakes reviews and teasing replies, where a plain meh would feel too short and a full explanation would kill the humour.
Über diesen Sound
Mais ou menos sound from the Brazilian comedy show Panico, repeating the phrase in a drawn out way for unsure, mediocre or in between reactions.
The clip is a looped voice line repeating mais ou menos, the Portuguese phrase for more or less, said slowly and flatly with long pauses between each repeat. The delivery gets less confident each time, turning a simple answer into a drawn out shrug you can hear. It lands as funny and awkward rather than informative, which is why viewers instantly read it as a lukewarm reaction to something that was supposed to impress but only halfway worked for anyone watching.