Grim dawn GOG version, can't play multiplayer

Reason is that to play grim dawn online it has to start from the gog launcher, AKA gog galaxy.
Installing GOG galaxy on lutris and then launching the game from there didn’t work for me, the game starts, but it just gives me a black screen with the game cursor that I can, however, move.

I found a workaround on reddit:

It did not work for me however.
Just to make sure that I followed the instructions correctly, here’s what I did:

My system, shamelessly copypasted from screenfetch (I hope it will suffice):
OS: Linuxmint 20 ulyana
Kernel: x86_64 Linux 5.4.0-42-generic
DE: Cinnamon 4.6.6
CPU: AMD Ryzen 5 3600 6-Core @ 12x 3.6GHz
GPU: AMD Radeon RX 5600 XT (NAVI10, DRM 3.35.0, 5.4.0-42-generic, LLVM 10.0.0)
RAM: 4898MiB / 32126MiB

If not, I’ll try to provide better info right away and the next time I won’t try this lazy quick fix.
Anyone has any suggestion? I COULD run the game on a virtual machine, but I’d rather avoid that.