@stelboy hello, try Reset the network settings of your phone. To do this, go to Settings / General administration / Reset. You do not lose personal data, you have to reconfigure the wireless connections.
Another step would be to clear the cache and data of the Bluetooth app. Access Settings / Applications activate Show system apps / see screenshot / and look for the Bluetooth app. In storage-clear cache and data and check again. Greetings!
@stelboy: Are you playing media that is stored on the phone itself, or are you using a web based streaming app? If it's the latter, try playing a song that is stored on the phone, as this will help to determine if the problem is potentially stemming from your Wi-Fi or Mobile Data connection.
@stelboy: Can you try heading to Settings > Sounds and vibration > Separate app sound > Turn on now (toggle the switch) > App > Samsung Music > Audio Device > Select your house stereo, and let me know if you notice an improvement with this setup?