Hi @ahashem 
There is a comment on this Quora thread How do you export a single band from a multiband raster in QGIS (qgis, raster, qgis 3, band, data management, GIS)? that I think may help you, it states the following: 

“In QGIS, you can export a single band from a multiband raster using the "Translate (Convert Format)" tool from the "Raster" menu. Here's a step-by-step guide on how to do this in QGIS 3:

1. Open QGIS and load the multiband raster dataset that you want to extract a single band from.
2. Go to the "Raster" menu at the top of the QGIS window.
3. Select "Conversion" and then click on "Translate (Convert Format)".
4. In the "Input layer" field, select the multiband raster dataset that you loaded in step 1.
5. In the "Output file" field, specify the location and name for the output file that will contain the single band.
6. Under the "Creation Options" section, you can specify the format and other options for the output file. Make sure to select the appropriate format for your needs.
7. In the "Processing" tab, scroll down to the "Additional command-line parameters" section.
8. Enter the following command in the "Additional command-line parameters" box to specify the band you want to extract (replace eband_number] with the actual band number): -b rband_number]
9. Click on the "Run" button to start the conversion process.
10. Once the process is complete, you will have a new raster file containing the single band that you specified.”

Check out the rest of the thread for more info that may be able to help you with your workflow.

Hi@ elyhienrich

Thank you so much for your detailed explanation. 

Ahmed