You need the Magisk Camera2API module installed, then get Snap Camera HDR and follow the settings in the screenshots. I get the most crisp 1080p120 footage of any phone I've seen due to the much higher bitrate. This app is also probably the best photo/video app on the market because it's so customizable. Depending on how you like your footage, I'd say mess around with the sharpness settings as it changes how the image looks by a huge margin. You need to enable "advanced settings" in the "other" tab beforehand