We seem to have that control, since it's possible to set a global time for the notifications, but not all of them respect that. At the Reddit post below, you can see an example of that, where my Chromium notifications won't disappear until I close them. https://www.reddit.com/r/kde/comments/qnhi6u/is_there_any_way_i_can_limit_chromium/
Going to look into it.
Hi, can you post your problem to https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/1180 ?
Patch was rejected upstream on the basis that apps with buggy behavior should be fixed instead. :)