If you want to record a gameplay video on your Oculus Quest 2 with commentary voiceover–you came to the right place.
I made a video showing how to do this, including syncing your recorded audio with your gameplay video using Audacity and Davinci Resolve–both free software.
In general, you need to record your gameplay on your Oculus Rift and the audio using headphones connected to your PC. The commentary audio will be recorded to Audacity and the video to your Oculus Quest 2 headset using the built-in video recording feature.
Once you finish, you bring the video files from OC2 and the audio saved from Audacity into Davinci Resolve (I used version 17 beta in the video guide).
Then, you sync the audio layer with the video layer, cut and trim the video when appropriate, and render/export it as a new video.
You can then upload the video to YouTube.