Sorry - my reply won't be really helpful to you, but I still want to say it because I think I have a bit different perspective on that problem and maybe that will be of use to someone.
I actually use that "forgot for half a year" approach to "curate" my wishlist. I usually aggresively wishlist a bunch of games during game events and so on, and then, about once a year I return to my wishlist and ask myself, if I still remember what were in those games that caught my eye, are they still interesting to me? If I do not, and looking at trailer and/or screenshots does not hype me up again, then it does not worth spending on (at least right now). Then I remove those that I decided to not play at all from the wishlist.
Not the one you have been asking, but you can eigher install Lutris, and then install GW2 from there, or download it on Steam. Those are 2 fairly straightforward ways. If you have an ArenaNet account (rather than an account binded to Steam), but still want to use Steam as your launcher - just write "-provider Portal" in launch options.