How about just one (or two) of the inexpensive “solar generators” with 3600-7200 watt pure sine wave outputs? (Charges from wall, solar panels or both. Also configurable for either only 120v or split phase or just use the 15/20a outlets on the things)
Would also serve as normal power backup when power is out… unplug stereo and use power for required loads..
They are getting better and less expensive all the time. (And no permits/electricians required unless adding the home interface box for critical loads.)
Dual use, “clean” power, equivalent price in the end and no grid power used for audio. Just an idea..