I'd say dedicated npub. Make thing easier and if you decide move on, it's easy to transfer if someone takes up the torch. Plus I also create different feeds list for specific subjects so this helps. Feedback will be much easier to sift through. Plus you can post links of your research and get further feedback you can reference in your podcast. Then you personal npub could be about your personal battle with your homelab/rv Shenagans which I've enjoyed when you do post them.