I disagree with the people here saying that no image is better than a camera feed. As an individual contributor and trainer myself, multiple times, I've found out that looking at someone explaining something in itself adds value. It doesn't need to be a sales pitch, you can discuss something with a colleague with a shared whiteboard, and still I appreciate seeing another one, their expressions, face complexion, mood, even their cats, dogs, etc.

That doesn't subtract to the fact that audio is the stronger medium. A great mic setup is orders of magnitude better than a pretty face via a DSLR. Podcastage has been one of my favorite youtubers on the matter since last year, https://www.youtube.com/watch?v=hEMZa5VN3Zw, and in that video he somewhat proves the point.

For camera recommendations, I agree with the majority that it needs to be a reliable setup. I was not a fan of DSLR with capture cards precisely because of that. I recommend AverMedia line of 4K webcams which have good defaults, amazing glass and have a great resolution and adjustable depth of field. In the past I used an Aver C340 4K which is amazing, but bulky, and now more recently I use a PW513 which is way better than anything Logitech has to offer.