I own 2 copies of the game (1 via Steam and 1 via the standalone Launcher).
I installed the Steam version and until now, used the “-provider Portal” Steam Launch option to switch between them. With Lunar new Year approaching I decided that, typing 2 words to change Versions, is too much of a hassle and looked for an easier solution.
Turns out, it’s really simple: By adding the GW2.exe, from the Steam installation, as a “Non-Steam Game” you are able to create differnt Shortcuts, with differnt Launch options, for the same Game.
Yeah, steam launching is a completely different beast. I doubt any of the launchers can handle it, since it requires a fresh-ish and valid token.
The way the launchers typically work, is having you save your credentials within the GW2 launcher, then storing the encrypted launch data away and shuffling it around as needed. You just can’t do that with Steam login.