The reason season 2 has not been announced is because Amazon is trying to buy the rights to either the anime or the company. Comcast is also in this bidding wars.
The company currently doesn’t want to be bought out because ironically when their competition got bought by these American companies, the anime they produced stopped being made.
This anime studio is trying to decide between getting half a billion dollars or making season 2.
The last major anime series that went through similar situation and took the money was “No Game, No Life!”