That and counterfeit parts ...
Yes, but let's give credit where credit is due. I see no evidence of fake components in Topping gear or even this Ayima stuff. I harp on about poor design, especially thermal considerations, because I am old school. Whatever the rating is, the device must be able to deliver/produce that power/output indefinitely. Not just a second or two at 10% THD before shutting down/exploding.
A power amplifier, regardless of its topology is going to produce heat. That heat needs get out of the device, out of the casework and dissipate into the air or else...
That's expensive. Expensive in thermal considerations, power supplies, construction etc. Our Chinese friends overrate their gear in terms of power output and underrate their ability to get rid of waste heat. That leads to failures, shutdowns and disappointment.
They will learn, just as the Japanese and the UK (English) learned. I would say the UK designed amps of the 1970s and even into the 1980s were simply terrible when it came to continuous power delivery, especially in hot climates like parts of the US and Australia. Quads for example just blew up. Sugdens cooked themselves.
Over engineering solved the problems people couldn't predict. Those dusty cupboards with no air. Those humid, seaside places where the "significant other" placed a potplant on the amplifier, etc.