Will an Amp change improve my system ?

For some of us, less is more.  I went from full on separates to a one piece system and couldn't be happier.  I sold all my McIntosh separates, and my Bluesound equipment and purchased a Linn MDSM all in one unit.  It has everything built into one unit.  The only other thing I bought to make it all work was an iPad to use as the interface.  I could use the Linn app on my Mac Mini to control it, but prefer the iPad.  If I am in the other room I can even use my phone to control all but the TT remotely. I have my TT and my Mac Mini (used as a music server) hooked to it.  I stream Qobuz, play any of my 8,000+ ripped songs, and my albums.  All without a lot of clutter of cables.  Everything but the TT is connected wireless over my mesh router.

Hegel and Harbeth have great sonic synergy, I'm thinking about getting the Hegel H400 + Harbeth m30.2 xd combo someday.

"I like my current system and wonder if an amp change would improve it significantly ?"

Probably not. If you are using the Schiit front end components and already are using the tube section on your Freya+, adding more tube amp effect or Class-A in lower-power amps won't likely add much to a system you already enjoy that has 140 WPC.

IMHO an amplifier change can really change the system sound. But so can a good preamp. Or a speaker change. Or room treatments. But I don't have any direct experience with any of the components that you currently have, so .... YMMV.

Your system seems already thoughtfully worked through with very good quality components. The Freya+ is an excellent preamp in the kind of system you have, it affords you three different processing modes, two with gain, one with tube gain and tube rolling is very easy if you are inclined to experiment. The Freya+ volume control is very precise. (It is easy to understand why that preamp is so popular.) Your amp is high quality with plenty of headroom. With what you have already, I doubt adding class A amplification or a tube amp will do all that much to improve what you already like in the room you have with the system you have. Pairing a tube preamp with a good quality solid state power amp is an excellent way to get the "tube sound"--the warmth, "airiness" and expanded soundstage everyone using tube gear seeks--while getting the power you need to drive low-sensitivity speakers in the 85dB range. If you want to try some small adjustments, changing out the tubes in the Freya+ would be the place to start.