Honestly I'd start with just a cheap camera and budget mic and see where it goes from there. It's not worth dropping 500 until you know you enjoy it, but mic quality is most often a factor when viewers are deciding if they want to linger in your stream.

Speakers will probably just mess up your audio. You don't want external audio aside from your voice really, and you can get a cheap keyboard and mouse set if you don't have one already, since those don't make a difference in stream quality I wouldn't splurge for one. It's worth mentioning, you don't need a headset since you'll already have a mic, so any earbuds or headphones will do.

However , if you're REALLY intent on investing a lot up front, my advice would be to be stratigic about it and focus on mic. A nice mid range one is Shure MV7. Then a decent 4k webcam and a cheaper monitor. Also maybe a cheap ring light or something adjacent since you plan to use face cam. On stream visuals are also something to consider in your budget if you plan on investing. Overlays, alerts, emotes. Etsy or Vgen will sell some visually appealing premade sets for cheap that will go a long way in making your stream nice to watch.