thanks for the advice, the issue was simply solved by forgetting and repairing the device, I'm not sure, but there was an interference from my bluetooth headphones that I tried switching off, anyway the article below helped a lot with tackling the issue, I put it here so others can use it if ever encountering this issue:
Trying to connect Alexa to Vizio soundbar? Here’s a guide that’ll help you do it by Bluetooth and AUX, the choice is yours!