Quick note: occ user:add --display-name="Foo Bar" --generate-password someuser4
occ user:auth-tokens:add -n someuser4
This shows something like:lDY7D3nsaZzzQVg8nvs45xwdSPhIIZDzI8QFL2vs7XI6PrpbvZJ15cJyqBCbEQL4sZDGTS9c
Add this app password to the kdewallet under Nextcloud:
passwords: someuser4:https://nextcloud.example.com/:0 (cli recipe will follow)
Now add a config to ~/.local/Nextcloud/nextcloud.cfg that includes someuser4 as username.