POLK MagniFi MAX SR problem with firmware

I have two Magnifi MAX SR devices. I've never connected them to Wi-Fi. Yesterday I decided to connect. They updated to the latest software on their own.

The first device downloaded firmware 136 after connecting to the network – it works fine. The second one also downloaded it, but now I can't use it.

When the volume is muted, I can hear the subwoofer. If I turn up the TV volume a bit, the subwoofer plays louder. The SR is very loud from the lowest level – if I set it higher than one or two stops, the SR can play loudly and the sound becomes distorted. Sometimes, I hear crackling sounds, and I feel like the speakers are about to pop out of the housing.

I tried a factory reset, but the same thing happens.
When I turn on the device, I hear a loud hiss for several seconds.

The Power Strip and Power Strip sound decent, but when I connect the Power Strip, the Power Strip makes a noise – the Power Strip is incredibly loud, and the Power Strip sounds completely different.

I also noticed that it can adjust the volume on its own.

The entire set was sent to the service center for a paid repair. After a few days, they returned it to me with the information that it was beyond repair (damaged motherboard). I guess I should buy an expensive one. The manufacturer no longer supports the MagniFi MAX and they don't have the motherboard.

I have the impression that the service center doesn't want to mess with such "cheap" equipment and they're wasting their time. So it's best to "ground" the customer and ground the equipment. What's their business? They haven't even tried to upgrade/downgrade it. They're burying their heads in the sand.

This is absurd to me. Even now, after updating the software on one device, it's unusable. Nobody cares about anything. They don't care about the customer. You have no warranty - buy a new one.

Please help.
Does anyone have a firmware file with version 136 or lower that I could try to save (manually update) my equipment, which suddenly became unusable?

Have a nice day.
I would appreciate any help.