When a presentation slide contains bullet points, highlight the point you are talking about and darken the rest.
How to Create a Dim Effect in – Microsoft PowerPoint 365
Add the Dim Text effect to bullet points in your PowerPoint presentations to help your audience focus on your content. This setting fades the text of your previous point into the background, but remains visible. Your current point remains front and center.
Dim Text Using Animations in PowerPoint:
Open the presentation and go to the slide where you want to dim the text.