Hi there! They have wifi at the casino of the Yanggakdo Hotel which is in the hotel's basement. You need to buy a chip (10 USD) in order to be able to be in the casino and can then use their wifi. Please note that the DPRK has had its borders closed since January 2020. On our last tour, which ended in January 2020 we were able to use the casino's wifi.
The connection can be poor sometimes, when making voice calls it can get a bit choppy sometimes.