htpc, nas and library update

I'm not sure which road to go with this:

tl;dr: I would like to "simply" listen to music and playing movies in the living room. The only screen we have is a projector so the music (preferably movie too) should be controlled with a smartphone/pc. I don't want to wait for library to updates.

current setup:

nas (debian - omv) → raspberrypi3 (kodi) → hifi amp (aux) | projector (hdmi)

issues:

My main gripe with kodi is the database update: kodi doesn't sync new files directly with the server and the android "kore" remote need to be updated as well.

When I add a new album I want to listen to I either have to force a scan which mean powering up the projector or wait long enough for the scheduled scan to do it's job. Both are too cumbersome and the scan is really slow, like, why does have to read the entire library again?

Atm I just play the album from my computer or phone...

The second thing is that the the pi analog output is not "hifi" while the NAS motherboard has a nice audio chip (but I'm fine getting a DAC).

current plan: ditch the pi and use the nas as a htpc, it's powered on all the time anyway. But I don't know what software(s) to install.

I don't care for the nice gui, artwork and whatnot, it always fails at some point, a file explorer is good enough for my use, I just want to be able to play a file remotely.

I'm also a bit worried about installing X11 on OMV and I like the separation between htpc and nas.

Thanks for reading, I hope it makes sense, maybe i'm just missing a plugin for kodi, I dunno.