The new controls should arrive later in 2020.
You can expect a handful of other improvements as well. You'll see a specific conversation view with threading, and the discussion interface that first popped up in Twitter's testing app will reach the main app in the months ahead. Lists are getting improvements too, including customization of the list display as well as screens that help you find useful lists.
This won't prevent unsolicited mentions, and you may still have to deal with caustic direct messages if you leave your DMs open. Still, this could significantly change how many people interact with Twitter. You may be less likely to abandon the service if you know that you can limit chats about hot-button subjects to those people who can meaningfully contribute. It could also encourage celebrities and officials to post without facing a glut of less-than-helpful responses. Simultaneously though, there's a risk this could reinforce social media bubbles where people only hear from like-minded individuals. You may need to expose your tweets to replies if you're interested in expanding your mind.