The quality rizz was popularized by streamer Kai Cenat on Twitch and later YouTube in the summer of 2021. To us olds, Kai is probably most well-known for accidentally starting a riot in Union Square, NYC earlier this August. It’s thought to be a phonetic clipping of charisma. The word’s usage took off on TikTok in mid-2022, giving rise to incredible explainers like this one from Defector: https://defector.com/livvy-rizzing-up-baby-gronk-explained

The KnowYourMeme history of the term has more detail for the curious: https://knowyourmeme.com/memes/rizz-unspoken-rizz