NAD C326 and Q Acoustics 2020i

I'm surprised you are finding this combination harsh, as this is the last criticism I would level at the NAD.  The Rotel is only going to be a sideways move, though there is a chance you might prefer its presentation.

What are you using as a source?

Combination of logitech squeezebox touch and nad c545.

OK, both good sources.  I can't particularly see a weak point in that set-up.

How are the speakers positioned?  What cables are you using?  What is the room like - hard or soft furnishings?

Sorry to fire so many questions but answering them will enable us to help you along.

How long have you had your C326? I found mine fatiguing and forward in the upper mid/lower treble from new. It sounds nothing like that now though, I consider my B&W speakers to be fairly neutral so if the NAD was harsh I'd hear it, as I did at first.

I'm not familiar with your speakers, but maybe they are a touch on the bright side or room acoustics and/or positioning could be the issue? I very much doubt changing the amp will bring the changes you're after. The C326 BEE is a smooth weighty amp.

Being totally alien to your speakers, I've done a little research on them and it reinforces to me that your NAD amp isn't at fault here. I'm not saying your speakers are, but if everything is fully ran in, well set up/positioned with good cabling, then I would be pointing the finger at the speakers before the amp. 

Reading consumer reviews on the speakers a few people find them bass light, which would be a contributing factor to a harsh sound.

What about trying some other speakers with your NAD amp? See if that changes things for the better? If not maybe have a go with a different amp.

I would try some Monitor Audio BX2 speakers............works perfect with the NAD C326.