Here's the comparison between DJI Osmo Action 3 and GoPro  Hero11 Black.

IMAGE SENSOR SIZE Osmo Action 3- 1/1.7-inch Hero11 Black- 1/1.9-inch

EFFECTIVE PIXELS Osmo Action 3- 12MP Hero11 Black- 27MP

VIDEO RESOLUTIONS Osmo Action 3- 4K: 3840×2160@120fps 2.7K: 2688×1512@120fps 1080p: 1920×1080@240fps

Hero11 Black- 5.3K: 5312×2988@60fps 4K: 3840×2160@120fps 2.7K: 2688×1512@120fps 1080p: 1920×1080@240fps

SCREENS Osmo Action 3- Front: 1.4-inch, Rear: 2.25-inch Hero11 Black- Front: 1.4-inch, Rear: 2.27-inch

WEIGHT Osmo Action 3- 145g Hero11 Black- 127g

BATTERY Osmo Action 3- 1770 mAh Hero11 Black- 1720 mAh

MAX VIDEO BITRATE Osmo Action 3- 130 Mbps Hero11 Black- 120 Mbps

DIMENSIONS Osmo Action 3- 70.5×44.2×32.8 mm Hero11 Black- 71.8 x 50.8 x 33.6 mm

PRICE Osmo Action 3- USD $329 Hero11 Black- USD $399.98