As for a lack of system tray icons, the practical upshot is that my system bar isn't littered with multiple special snowflake applications, each with their own unique icon art style and mismatching proportions.
Plasma Desktop's System Tray widget that lets you hide icons you don't want to see. You can disable the widget, or configure it to show no icons at all.
With default being off, it is applications that have to be careful. They can use it, when they detect it is present, but cannot assume it anymore.
System trays exist on most platforms, and apps, especially cross-platform apps, will sometimes assume that they exist. I prefer to use a system that can handle those apps.
I prefer when applications do not assume that it is available at all; if they do, they are broken. Applications, that force themselves on the user upon startup, then sit in the systray and are resisting the user that is trying to close them are outright black UI pattern.
Now, due to another bug in Windows, the overflow menu has remained open and must be manually closed. The third bug here is when I alt-tab out of LastPass, it doesn't take me back to the most recent application; instead it dumps me on the desktop or some other program at random (why is the desktop even there in the alt-tab menu?)
I'm not against apps running in background, just that monolithic implementation with systray is the wrong approach. Android has shown a good model: background service that cannot talk to UI, but can send notifications or communicate with separate UI app. With this model, user has control over what is running in background or what started on login time by system (not app-specific!)-provided tools, like systemd user units under Linux or LaunchAgents under macOS. When the user wants something off, it will be turned off in one place, with no ors or buts or other black patterns that prevent user turning the application off.
Looks like there are still tray icons, they just need to be implemented differently?