Lolzarella: I don't appreciate the surprise change to 2.0 Beta at all. I don't like the new layout or the black background. I liked the old layout with my stuff being over in the left-hand column and being able to have it sorted by tags. My tags are tools for me as some games trigger motion sickness and some games like a lot more than others so I want the things I like best up top. I'm also tired of being forced into a completely different UI layout that has a bunch of junk clutter features that I don't use and that takes away the things I do use. At least give people the option to rearrange the layout of the page or toggle off the useless features.

obliviondoll: Short term solution:
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/how_to_keep_galaxy_v12_client_and_avoid_the_forced_v20_beta_update

Use instructions in the above topic to revert the client to the most recent stable build (which was a 1.2 version, not 2.0 because that isn't stable yet). Regain access to all prior functionality. Use Playnite or some other multi-platform launcher if you want one of those. They do their job better than Galaxy 2.0 does anyway at this stage.

Long term solution:
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/open_letter_to_gog_and_message_to_support

Contact support. Wait apparently at least 3 weeks and counting without a reply. Hope.