I have only heard of accusation of chinese backdoors but no one has every found one. They have found bad security practices which was also typically found thru life cycles of western software.
Loongson engineers are working w the Linux maintainers to get Loongarch support. "Linux" works on Loongson cpu now, but its the matter of maximizing the chip's potential.
"Chromebooks" have proliferated with limited processing power and very little native app support, so Loongson can become more mainstream in certain markets. However the biggest hurdle would be getting the price down to be competitive to intel/arm at similar price point.