There is no difference between 2-ch and multichannel at all. The differences are between "direct" which passes the signal through unchanged (except for VC) regardless of the number of channels and non-direct which processes the digital inputs and which takes advantage of the DSP capabilities. It is those capabilities which endow it with its best performance, imho, because your rooms acoustics and speaker/listener positioning do not change regardless of the number of channels.
I have no other suggestions within your price range.
I have no other suggestions within your price range.