Halo Infinite was supposed to be Microsoft's big exclusive launch title for the Xbox Series S/X. However, due to the COVID-19 pandemic, 343 had no choice but to delay the game to its current holiday 2021 release date. But, if you asked the internet, they'd probably point to the game's ugly graphics that definitely did not look next-gen as the reason. The best proof of this is the infamous monke meme that went viral last year.
343 gives Monke meme a much-deserved glow-up
Brutes are one of the races that players will encounter in Halo Infinite. They're supposed to look big and scary. Unfortunately, the image that circulated in 2020 was anything but. The Brutes looked like they were made for a game that was going to release in the 2000s, instead of something for the Xbox Series S/X.
343 is probably aware of this (who wouldn't be?), which would explain why the leaked in-game screenshots of Halo Infinite show a reworked look for the game's brutes.