I list my games in an HTML file on my computer, and made it so I can launch them from any web browser instead of the macOS Finder. I suppose that would be equivalent to using GOG Galaxy since it seems to be a modded HTML viewer, so I don't have that installed at all. Galaxy is too limited in customization, can't keep notes in it either.
However, instead of launching games from my HTML file, I've been simply launching games from
dired in
emacs. I've been using my HTML file just for notes on special installation instructions (WINE, ScummVM, extracting from .pkg), links to the downloaded PDF manuals and hintbooks, and recent purchased games to complete within 30 days.