Desktop client 3.13.0 cannot add new account

In the process of moving to a new laptop, added the first NC sync set, then wanted to add the next account - but there’s no “plus” button.

Specifically:

I click the tray icon, a dialogue comes up showing the currently active account and its status; at the top left there’s a button showing the account’s login name with a dropdown arrow. I click that, I get a “list” of accounts (with the one entry) and there’s no plus “+” button below. I then checked the old laptop, which shows the list of accounts to choose from - but also lacks the plus button.

The 2 laptops are different Linux distributions, one is Xorg, one Wayland; they are both KDE, and probably key, they are both Plasma 6 (one is 6.0.5, the other 6.0.4).

Manually adding the server/account info in .config/Nextcloud/nextcloud.cfg is a clunky but functional workaround.