Nah, back then I was looking for Mac version to try. Then it turned out that native Mac version requires physical disc to be mounted; so I begin to look for a way to workaround that requirement. When I found an old Reddit post which indicates a sale on GameAgent which was the online digital store of Mac porter Aspyr, I assumed that there had to be a digital Mac version that doesn’t need physical disc to be mounted. But as GameAgent is long gone and even Internet Archive: Wayback Machine cannot revive the link, I was unsure. Recently, I found original URL of ETQW’s Mac version on GameAgent, it turned out that GameAgent too was selling boxed edition of ETQW for Mac which means there was indeed no official digital version of the game on sale. So I removed GameAgent URL from the original post, that’s why the thread bumped to the top which is quite weird actually…
I can safely say that only available digital releases of ETQW for PC in the West were the 3 stores that I listed in the original post. There may or may not be other digital versions for East Europe and/or Far East since the game was distributed by different publishers there such as Soft Club. As for the Mac version, I found an unofficial solution to avoid disc mount requirement if anyone interested.