Overview page: https://www.gog.com/en/anniversary
Direct sign up for Galaxy Linux beta: https://www.smartsurvey.co.uk/t/YEF5EV/
I use Lutris as my launcher in Linux and the level of convenience to run Windows games in Linux with it is slightly superior to Steam (superior mainly because I like to run my games inside a sandbox with networking disabled, which I can easily do in Lutris but not Steam, plus I don't have the launchers always running in the background and it's very rare that I have to wait for Lutris to update when I want to run a game and start it, whilst with Steam it's pretty common that I try to start a game and then spend a few minutes waiting for Steam to update itself and/or the game, when all I want is to run the bloody game and don't care about it being the latest version), though for most people it should be around the same or maybe even a bit more for Steam if you care about automatic updating of the games before they're run (which Lutris won't do for GOG games - it will fetch and install game updates but you have to tell it to do it) and certain Steam API facilities such as cloud-saves and showing achievements to your friends.
My total failure rate of running Windows games from GOG using Lutris as the launcher is about the same as that of running Windows games from Steam because Lutris too does the whole Wine + DXVK thing and has launch scripts for most games, though Steam does seem to have problems with AAA games from a certain generation (around the 00s) that won't run in Linux whilst the pirate version of the same game runs just fine from Lutris, which is probably due to the DRM for those games back then which I remember was a real pain in the arse and which is still present in the Steam version.
So my no-DRM thing is also a bit about running my games in Linux - because sometimes DRM gets in the way of that - though it is mainly about ownership and controlling myself when and how I run the games I bought and not actually losing access to a game because it was taken down from the store.
In fact I have no intention of using a Linux GOG Galaxy as my launcher in Linux, same as back when my gaming PC was Windows I didn't use the Windows one, I just hope GOG finally making one for Linux signals that they're taking Linux gamers more seriously and maybe they'll do like Steam and contribute some open source code to the gaming ecosystem in Linux, as that will benefit us all.