YouTube will allow users to create nicknames

Nicknames in the form of @nickname will appear on the service this week, gradually for different users. When it’s your turn to choose a nickname, you will receive a notification.
YouTube

According to YouTube, the first to receive such notifications are those who have a high overall presence on the platform, the number of subscribers and activity on the channel. It is worth noting that the nickname and the link to the channel are different things, and the links will remain.

We want to enable creators to identify themselves as uniquely as their content, giving viewers the confidence that they are interacting with their favorite creators.

YouTube

Nicknames will work as a user ID in the link, comments, YouTube Shorts (similar to Tik Tok) and in general across the entire platform.