I owned a Primaluna Dialogue Premium for a couple of years. KT88 tubes made the best sonics for my ears with better bass, more power, and a little extra body in the midrange while smoothing out the top end.
That said, I know the veil or miffed sound you speak of. I noticed it most clearly when trying an LTA Z10 with half the watts of the Primaluna and heard that veil lifted with better bass and just as much midrange beauty. Doesn’t help your current situation, but a good place to try next.