Advice on choosing a camcorder

While I am not particular familiar with any of the camcorders you mentioned, here are some general thoughts:

Firstly, you will need to decide on what RESOLUTION you want to shoot and deliver (upload to youtube) your videos in. 1080p (called Full HD) or 4K would be the most common. (The video you linked to by Ching-Yun Hu was only 720p, so even less than 1080p full HD)

IMHO, 1080 should be fine for your needs, but maybe you would prefer the extra resolution of 4K? This would allow you to crop in somewhat in post.

Secondly, the lower the light, the more the image benefits from a larger sensor. I don't know what size sensors are in the camcorders you mentioned. But in general, bigger sensors are better, but in good lighting, it won't make much of a difference.

For your needs, you don't need to worry about things like maximum telephoto focal length or anything like that.

And if you are on a tripod, you won't need to worry about things like In Body Image Stabilization (IBIS)

And you don't need the best autofocus. You just need Single AF (or even manual AF). Don't use continuous AF for such a performance.

Basically, what I am saying is that if you are trying to emulate the look of that Ching-Yun Hu video you linked to, most any camcorder that will record 1080p (Full HD) for unlimited time and has good battery life will do.

As for recording sound to an external recorder, that can be a good option, although I understand that for a long performance, there could be "drift" where the sound slowly starts to lose sync with the video.

And finally, a practical tip (or two). If you are going to be syncing audio recorded externally with your video, then it is best to start with three hand claps (with your hands in the video frames) followed by a quiet pause of about four seconds or so. This will make it easy to sync the video track with the audio track.

The four second pause will make the "spikes" in the audio track stand out so you can find them quickly. Plus, it will give you a four-second sample of room noise, so when you do noise reduction on the audio track, you can sample the room noise and then know what to reduce.

Also, best to try and "treat" your room to reduce reverb and external noises. Turn off fans and turn off whatever electrical devices you can to reduce RF interference / hum.

And finally, maybe investing in two less expensive cameras would be better than having a single more expensive camera??? Having people sit and watch ONE camera angle for a long time can get pretty boring.

Just saying...