Perfect, I did it
Now everything works perfectly.
The audio is perfect.
I bought some cables for testing
In summary you need:
1 jack cable (splitter) composed of 2 females and 1 male
this is used to hear the audio while it is being recorded using headphones or external speakers very comfortable and practical.
1 male jack cable to directly connect the audio output to the audio-IN port of the PC in use.
And enable in this case on windows 10 audio mixer.
Then there are the settings to be made in OBS
I won't go into unnecessary explanations but in summary it works perfectly with Morphos for those who want to record videos.

Here is the final result, I am very happy with the result
https://www.youtube.com/watch?v=LrCRXX3Hl3Y

@cip060
Thanks,for the tip and it was very helpful I added a splitter for ease of use.

[ Edited by white 13.07.2021 - 15:45 ]