Using the default "Lens Flare" that comes with your software (the one with the rainbow circles) is an instant mark of an amateur. Always use organic, real-life captured overlays.
You do not need After Effects to use overlays. You can download ready-made MP4 or MOV files with alpha channels. Here is the 2025 landscape of overlay resources. overlays for video editing
Novices lower opacity. Professionals use blend modes plus opacity curves . Using the default "Lens Flare" that comes with