UPDATE:

I've been busy in real world, could barely get close to the computer. I've finally managed to get down to work and get to the bottom of this.

I've visited this link

https://github.com/spesmilo/electrum/tree/master/contrib/build-wine#windows-binaries

INSTALLED DOCKER

$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
$ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
$ sudo apt-get update
$ sudo apt-get install -y docker-ce

BUILT IMAGE

$ sudo docker build -t electrum-wine-builder-img contrib/build-wine

NOW COMES THE TRICKY PART FOR ME

$ FRESH_CLONE=contrib/build-wine/fresh_clone && \
    sudo rm -rf $FRESH_CLONE && \
    mkdir -p $FRESH_CLONE && \
    cd $FRESH_CLONE  && \
    git clone https://github.com/spesmilo/electrum.git && \
    cd electrum

and to build

$ git checkout $REV
$ sudo docker run -it \
    --name electrum-wine-builder-cont \
    -v $PWD:/opt/wine64/drive_c/electrum \
    --rm \
    --workdir /opt/wine64/drive_c/electrum/contrib/build-wine \
    electrum-wine-builder-img \
    ./build.sh

Excuse my noobness, but from this official windows binaries build page, if I understand correctly, you need to download a fresh clone from github.

BUT, my intention is to build from the file I downloaded, which is Electrum-3.3.8.tar.gz which I extracted to Electrum-3.3.8 directory. I only want to build Electrum Standalone Executable from this directory and not from a clone from github.

Is this the only possibility? Can anyone confirm? Yes / No

If cloning from github is the only possibility to do this, then I've set up an unrealistic goal from the start which only became apparent now

Waiting for your feedback