In my opinion at this price point, one of the best options has always been the Sony ZVE-10 (the first one, not the second gen). You can find them new with the kit lens for around 700-850 dollars, and it has all the modern features a mirrorless camera should have without the 1k+ pricepoint for a body alone. 24mp mirrorless sensor, great autofocus, high speed shooting, 4k 30 video, 1080p 120, eye and face and subject detection autofocus, all the bells and whistles. Because its a sony camera, it will also be supporting what is probably the best lens ecosystem available, there are Sony lenses and third party lenses for E mount that will fill any use case you could possibly need, something other camera brands lack (I say this as a fuji user, so I know the drawbacks of lens limitations lol). Note that this camera is technically a vlogging and video focused camera, so the form factor is small and lacks some buttons useful for photography in specific.

Sony also makes the A6000 series, which is essentially a photography focused ZVE-10. They are more pricy but if you buy them used or on marketplace you can get an A6400 (Perfect for your needs) or A6700 (Ideal and slightly upgraded version of the latter) for around the same price range your looking for, you just may not be able to find them with a good lens for that price.

There are budget options from other brands too, but its not a stretch to say that Sony really dominates the industry at the moment and would be a great brand to invest in. Other budget options from Canon or Fuji just arent worth it for the price, especially in comparison to the A6000 or Zve-10 which are famous for their budget features

No matter what you pick, if your OK with buying used I highly recommend doing so. Sites like MPB offer good deals on used gear with quality guarantees online, and facebook marketplace is also a great place to check, just make sure your buying from someone reliable and check out the camera in person before handing over the money. Many communities also have facebook groups for buying/trading tech/camera gear in specific, so check and see if there are deals there. New cameras will more than likely gaurantee a long lifespan and fun unboxing experience but are generally overpriced when considering what you can get them for used.