Way over-budget for your taste I guess but I still wanted to make a note here for representation sake.
Look into the brand Zidoo. I have Zidoo Z9X 8K, it's the best client I could dream of! ~250$
Cons:
Android based (outdated AF but still)
Maybe not so secure (http server always on while the device is on, atm)
Pros:
Very good support of Dolby Vision, 4K (8K maybe?)
Very pretty, both hardware and software very polished IMO
The remote is glorious, tactile with backlight
Lots of other cool things
Very snappy Android experience
it just works™
The audio downmixing works great, compared to the Google TV which was very bad
Way over-budget for your taste I guess but I still wanted to make a note here for representation sake. Look into the brand Zidoo. I have Zidoo Z9X 8K, it's the best client I could dream of! ~250$
Cons:
Pros: