What SQ value does a high end stereo preamp add to a network player?

Yes, i have seen this and with remote.  Seems ok. Considering.

it looks like crap, why is that?  And why not hear about it very much.

I like the goldpoint, too bad no remote.

so with only one source to a stereo pre, it seems unnecesary to get a pre.  
So if only these quality switchers had a remote.  

´´can i use x1 as a pass thru from ht processor for mains?´´  : no

But you could use something like that , from the Lumin to the power amp. and from the AV processor to the power amp.https://goldpt.com/sw2x.html

Then the quality of the power amp is important

Thanks, very helpful but its part of a ht system so i need a means to switch between whats using speakers.

Only use network player and av processor, ie no cd or turntable.

can i use x1 as a pass thru from ht processor for mains?

If the Lumin X1 is your only source,  Lumin’s Leedh Processing 
should be fine . No need for a pre amp.

The Lumin has a good attenuator, there is no discerible benefit from adding a pre since the output voltage of the Lumin is more than enough