The 1080p laptop webcam that's in Apple's latest models is quite a decent camera that benefits from the ISP in Apple silicon. Even the ancient 720p camera hooked up to that ISP managed an incredible amount of improvement over the Intel models.
I'd also venture a guess that many other laptops' built-in webcams can outperform some of these dedicated units, not just the ones that are Apple's iPhone R&D beneficiaries.
"Mic audio is always trash" – again, try a newer Mac notebook model. Apple has been investing serious R&D into laptop microphones, and I think competitors are taking notice and making their own improvements.
It might sound crazy to buy a second phone for this kind of thing, but I do think there are people who will get a better value out of actually just buying a second iPhone as a webcam/streaming camera compared to buying a dedicated professional camera.
Unlike a mirrorless/DLSR camera, you can also acquire smartphones with deep carrier discounts and long, zero interest financing. So, presumably, you could buy yourself a new phone, and instead of trading in your old one you could use that as a streaming webcam.
Don't forget that iPhones aren't just $1000 luxury phones, Apple's cheapest new model is $429 and will stomp all over any dedicated webcam on this list. If you jump on the used market you can buy something like an iPhone 11 or XR for under $300 or $200 and still have a really solid webcam (as a bonus, you don't have to care about the condition of the battery).