GoPro - HERO13 Black vs DJI - Osmo Action 5 Pro

These two are evenly matched on the broad strokes, with the decision sitting on which individual spec advantages weigh more for your use.

Pick the HERO13 Black if you care most about max video. The biggest gaps in its favor are max video.

Pick the Osmo Action 5 Pro if you care most about waterproof depth. Its strongest claims are waterproof depth.

Both ship with comparable max 4k fps, stabilization, horizon lock, so those specs don't separate the two — focus on the differences below.

Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity tells you both are well-rounded; the differences are about trade-offs, not quality.