You have another amp, so waiting 6 months to get a proper diagnosis and cost estimate is but a speck in time.
Meanwhile, check and see what they are selling for
https://www.hifishark.com/search?q=ayon+spirit
You might get lucky if the tube protection board has tripped. Surely it would have a reset
"The Spirit II is not a simple update, it is a new redesign featuring new circuit boards, tube protection board, add features like Pre Out or Direct Input for pure power amp operation and new pre-driver tube devices."
I agree with suggestion to swap tubes l/r, see if any change.