opening any game page in store gives me:

This page isn’t working
If the problem continues, contact the site owner.
HTTP ERROR 401

just me or gog?

Loading fine for me, admit-tingly I use Brave and Firefox.

Store game pages are working fine for me too, in the latest version of Opera on Windows 11, Opera One(version: 119.0.5497.40).

I'm not sure what difference that glorified Chrome with dipping mustards would make, but a 401 suggests that there might be something wrong with your certificates.

There've been a few scattered reports from various people about this over the last couple of weeks. (Here's one on reddit.) Each of them cleared up after a couple of days without a clear cause or solution. One report I recall mentioned that it started after the person changed their username, and this thread was from someone who switched login method away from google. Did you maybe do either of those things, too?

You could try a hard reload (ctrl-shift-R), clearing cookies, or logging out, closing the browser, and then logging in again. Or just wait a couple of days. :/