Best Camera for YouTube Videos ?

I'm looking to up my video game and start producing higher-quality content for my YouTube channel. I've been using my smartphone, but I think it's time to invest in a dedicated camera. I'm wondering what you all consider the best camera for YouTube videos these days?

I'm open to DSLRs, mirrorless cameras, or even high-end point-and-shoots. My budget is flexible, but I'd like to keep it under $1,500 if possible. I mainly shoot indoor talking-head videos and occasional outdoor vlogs.

Some features I'm particularly interested in are:

1. Good low-light performance
2. 4K video capability
3. Flip screen for self-recording
4. Decent built-in audio (though I plan to use an external mic)
5. Wi-Fi connectivity for easy file transfers

What are your top recommendations? Any specific models you swear by? I'd love to hear about your experiences and any tips you might have for a YouTube camera newbie. Thanks in advance for your help!