It shouldn't matter if it's marketed for office use. If it has the specs you need, which it sounds like it does, it should work fine for your use case. Double check that it has any ports that are essential for you before purchasing.
You may want to consider a fanless design which would be silent, as you mentioned noise is an issue. The performance may be ...
GPD is THE brand for such toys.
But your list of requirements I think isn't realistic (and in a way not even relevant.) Even normal big laptops don't usually match those specs so why would you look for them in a miny device and then expect it shouldn't even be overly hot... (And TBH, comparing to the RCA Voyager Pro which has 1 GB RAM why are you looking ...
Take a look at the Udoo Bolt or their other products. Basically that's an x86 SBC with proper RAM slots.
I forgot about dual Ethernet requirement. You could possibly go for a USB 3.0 adapter if it's acceptable.