I expect it will sound even better over the next month
Hopefully burn in will help
You think a class D amp will “burn in”? I just don’t understand this belief. Rest assured that it will not burn-in or sound better. Your solid state hardware sounds like it sounds, so just enjoy!
There are many reasons to want an all-in-one streamer, and many benefits to having one.
The question is, do any of those benefits or reasons apply to you?
If all you want is to listen to music over bluetooth, then you probably want the cheapest and best solution to do that. That doesn’t generally involve an “audiophile” piece of equipment, even though what you get will probably sound just as good as any of those.