gog galaxy 2.0
https://www.virustotal.com/gui/file/f653877f0e0af4d1bc85e979e7b218744c9e7e83d5ef55fec0c70897556e47e8/detection

gog galaxy downloader via JA3 Install
https://www.virustotal.com/gui/file/e0dbf03cb6d769c7b244d9add9e7dcdf9f21ba834d3f1ffb0ff3808a00087647/detection

Is there any offline installer to use for secure installation and succeeding Firewall configuration -after- installation?

I'am no fan at all of online-installers that change the code every hour ... this f's any security implementation.

[ISSUE RESOLVED]
AWG43, Ice_Mage

Yes. The same question was asked about 3 years ago with the solution provided.

https://www.gog.com/forum/general_beta_gog_galaxy_2.0/is_there_an_offline_installer_for_galaxy_20/post2

If you want the full GOG Galaxy installer that doesn't connect to the Internet, bookmark this JSON file. It will always point to the latest versions (as long as they don't bump the major version from 2). The page looks best in Firefox, but it can be made readable in other browsers with an extension like JSON Formatter.

As for the Virus Total results, those are some antiviruses no one's ever heard of identifying a generic threat, which is the hallmark of a false positive. The only one that identifies a specific threat is an antivirus from Belarus, with a barren Wikipedia page that just notes it's used on Virus Total.

Edit: typo.