For the talking-head stuff, almost any camera will be good enough if given enough light, so I'd suggest you concentrate on getting 1) enough light so your camera is at its native ISO, and 2) lighting that is flattering and creates depth and contrast in the image.
There are lots of videos on YT that show this, and the before/afters show what is possible. You don't need expensive lights either, there is tonnes of info on home DIY hacks using lamps and cheap shower screens as diffusers, etc.
The standard approach is 3 Point Lighting, like this:
This video is a good primer and talks about how to use (or avoid) existing light sources like natural light and ceiling lights etc.
Other videos that might be useful:
This video is longer but starts with a complete setup, so acoustics etc too.
Cameras get all the attention, but in the real world are some of the least important parts of the whole setup.
You're lucky in that you're building something indoors for one specific use in an environment you control and (hopefully) doesn't have to be portable and easy/quick to setup and pack away. With a bit of effort you should be able to get a great setup that works really well and doesn't cost much at all.