There is no issue with the speaker as it supports that out of the box via Rest API. The only mess is that smartthings/samsung does not fully support their own products, but Sonos and Bose. With the Multiroom apps you can control Samsung soundbars and Samsung multiroom speaker completely.
Android
iOS
For openhab there some guy trying to create a binding
var URL = ""
switch Command {
//Input mode
case "setOptical" : URL = '/UIC?cmd=%3Cname%3ESetFunc%3C/name%3E%3Cp%20type=%22str%22%20name=%22function%22%20val=%22optical%22/%3E'
case "setBluetooth" : URL = '/UIC?cmd=%3Cname%3ESetFunc%3C/name%3E%3Cp%20type=%22str%22%20name=%22function%22%20val=%22bt%22/%3E'
case "setWifi" : URL = '/UIC?cmd=%3Cname%3ESetFunc%3C/name%3E%3Cp%20type=%22str%22%20name=%22function%22%20val=%22wifi%22/%3E'
case "setHDMI" : URL = '/UIC?cmd=%3Cname%3ESetFunc%3C/name%3E%3Cp%20type=%22str%22%20name=%22function%22%20val=%22hdmi%22/%3E'
case "setAux" : URL = '/UIC?cmd=%3Cname%3ESetFunc%3C/name%3E%3Cp%20type=%22str%22%20name=%22function%22%20val=%22aux%22/%3E'
case "setRadio1On" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=0/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%221%22/%3E'
case "setRadio1Off" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=0/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%220%22/%3E'
case "setRadio2On" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=1/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%221%22/%3E'
case "setRadio2Off" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=1/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%220%22/%3E'
case "setRadio3On" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=2/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%221%22/%3E'
case "setRadio3Off" : URL = '/CPM?cmd=%3Cname%3ESetPlayPreset%3C/name%3E%3Cp%20type=%22dec%22%20name=%22presetindex%22%20val=2/%3E%3Cp%20type=%22dec%22%20name=%22presettype%22%20val=%220%22/%3E'
case "setAutoRadio" : URL = '/UIC?cmd=%3Cname%3ESetRadioAutoPlay%3C/name%3E%3Cp%20type=%22str%22%20name=%22cpname%22%20val=%22%s%22/%3E%3Cp%20type=%22dec%22%20name=%220%22%20val=%22%s%22/%3E'
case "getMusic" : URL = '/CPM?cmd=%3Cname%3EGetRadioInfo%3C/name%3E'
case "setNext" : URL = '/CPM?cmd=%3Cname%3ESetSkipCurrentTrack%3C/name%3E'
case "setPrev" : URL = '/CPM?cmd=%3Cname%3ESetPreviousTrack%3C/name%3E'
case "setPlay" : URL = '/CPM?cmd=%3Cname%3ESetPlaybackControl%3C/name%3E%3Cp%20type=%22str%22%20name=%22playbackcontrol%22%20val=%22play%22/%3E'
case "setPause" : URL = '/CPM?cmd=%3Cname%3ESetPlaybackControl%3C/name%3E%3Cp%20type=%22str%22%20name=%22playbackcontrol%22%20val=%22pause%22/%3E'
case "setReapeatOn" : URL = '/"UIC?cmd=%3Cname%3ESetRepeatMode%3C/name%3E%3Cp%20type=%22str%22%20name=%22repeatmode%22%20val=%22on%22/%3E%22'
case "setReapeatOff" : URL = '/"UIC?cmd=%3Cname%3ESetRepeatMode%3C/name%3E%3Cp%20type=%22str%22%20name=%22repeatmode%22%20val=%22off%22/%3E%22'
case "setShuffle" : URL = '/CPM?cmd=<name>SetToggleShuffle</name><p type=\"dec\" name=\"mode\" val=\"%s\"/>'
}
URL = "http://SPEAKER_IP:PORT" + URL
var Return = sendHttpGetRequest(URL)
Also here in the smartthings community there are some guys trying to bring more functionality in that is unfortunately not done by Samsung officially.
Unfortunately the HMI of the smartapp below also only has a source toggle implemented (maybe you can request this feature from the DEV):
BUT it is really disappointing Samsung does not make the most or even anything out of their product range and provides the best integration for own products.