Sorry to hear you're disappointed in the A10's. I had a little fiddling with the setup when I first got mine, but since then they have been a reliable part of my WiiM/Linkplay space.
I did not know that the physical volume buttons do not respect the L/R grouping -- in my use case I use the app exclusively. This is unfortunate for sure.
In regard to the sound -- I agree with
@hgo58 's suggestion -- forget about room correction and just use the tone controls. I think elaborate room correction is overkill (and maybe non-ideal) for a little speaker like this. Sounds like you need to move the bass slider up a bit.
Good luck.