I've reinstalled Artix from the latest stable LXQt ISO and updated all the packages to the latest version. After a reboot, I see this angry message on my login screen under the "Select your user and enter password" label. Luckily this message doesn't seem to affect the functionality - everything logins and works OK - but I hope you can fix this and get rid of this angry message.
(https://i.imgur.com/Wu73vbz.png)
I think this is a known issue with the Artix sddm theme. I expect it will be fixed soon. :-)
In the meantime, you could select a different sddm theme, till the Artix theme is fixed.
Best regards.
https://forum.artixlinux.org/index.php/topic,1536.msg10563
It was fixed yesterday.