You most likely installed something that either requires dunst or dunstify and also pulled the rest of conifgs, taking over the KDE Plasma notifications, or you did something else with the settings. Check your pacman log at the end and see what got installed and remove it, or see if Configure Event and Notifications has or not options.
Reinstall knotifications and knotifyconfig is you notice there are no opyions.
I’ve marked the below answer as the solution to your question as it is by far the best answer you’ll get.
However, if you disagree with my choice, please feel free to take any other answer as the solution to your question or even remove the solution altogether: You are in control! (I just want to avoid even more subjective opinions being posted and confusing you even more)
P.S. In the future, please mark a solution like this:
so that the next person that has the exact same problem you just had will benefit from your post as well as your question will now be in the “solved” status.