When I try to access those pages, I got a 404 error. Anyone can help with that? I opened a ticket, but got no response.

Go to your account, then to "Orders & settings" and finally to "Privacy". There is an option where you can enable your profile.

I tried clicking the checkbox to enable my profile. The page refreshes but the checkbox is never checked and my profile is never enabled.

Tried it on Firefox and Safari browsers.

same. in GOG galaxy i can access the setting and profile is enabled just fine, but on browser it isnt and cannot select the checkbox

also cannot look at anyone elses profiles apparently.

update. ok. this is a weird one. multiple browsers. this works the same on all of them.

if im logged in on the browser i cannot see my own or anyone elses profile or my feed.

if im logged out i can see can see my own and other peoples profiles just fine

I'm not sure. It's working for me.

Have you tried to refresh? => https://www.gog.com/user/refresh