It should only need to ask once per session. That is to say, I use both Opera and Vivaldi, between them I only get asked once (by whichever runs first) until I log out of my desktop. If I close Opera and do something else for a while then go back to Opera it doesn't ask me then either (unless I logged out of the desktop)..

Now, if it asks but you somehow lose the dialog (behind another window, or close it by accident or some such) then Opera won't know any passwords ... but it also won't lose them. If you close Opera then try again all the old passwords will still be there, as it couldn't save them because you weren't logged in to the password manager.

I presume there must be a way to reset the password manager, but I'm also sure you'd know if you had..

Sounds like the folder set as your default download directory doesn't exist. Go to Settings > Advanced > Browser and look for the Downloads section, make sure it is set to a path that exists and you are allowed to write (save) files to it.

As I said first, the obvious answer is to do the same thing you just finished doing, but make sure you recreate the accounts in the right order.

You mean, besides doing it all again and being careful to recreate the accounts in the right order? I could reorder the sidebar, but the dropdown is a different matter.

No. Opera's VPN is blocked in China.

Most often, reaching 100% without actually finishing is tied to a firewall that blocks "private headers". Check the settings in your "internet security" software.

No one has said how you do 2-factor authentication with only one factor ...

I think this is the wrong forum - I think they do mean the browser - but I still don't get it.

Any mail client will want to be able to read, send and delete email - otherwise what are you using it for? But this isn't the place for this discussion - this thread was about accessing Gmail through their website (using the Opera browser). I know, I'll split this thread and move your post (and my reply) to the Lounge.

@emc Is it still fetching mails properly?

We would prefer if you use polite language here - this is a user forum: there may be children reading.