Hide apps from the switcher
macOS ⌘ ⇥ cannot take an app off the list. In Tern, ⌫ hides the app, ⌥ ⌫ hides one window, and you can filter by title, for a while, or with a Focus.
Updated
What the system will not do
The macOS app switcher shows every running app. There is no exclusion list. ⌘ H hides the app on screen, but it still shows up in ⌘ ⇥.
The whole app
With the Tern switcher open, highlight a window and press ⌫. That app leaves the list until you bring it back in Settings, from the menu bar, or with a tern://unhide link. Settings can also add a running app.
Just one window
⌥ ⌫ hides it by exact title. The rest of the app still appears. If the title changes, the window comes back; use a title rule for that.
By title
A rule with a piece of text, or a * pattern, hides windows like Picture in Picture even when the name changes. It can apply to one app or any app. That is the path for floating players, inspectors, and other windows that only clutter the queue.
For a while
⇧ ⌫ hides the app for an hour (snooze). In Settings: one hour, until tomorrow, or always. When the time is up, the app returns on its own.
By mode and Focus
A mode (Work, Personal) is an extra set of hidden apps. Switch it from the menu bar. To turn it on automatically: System Settings › Focus › a Focus › Focus Filters › Add Filter › Tern.
Shortcuts and links
In the Shortcuts app: hide an app (always, 1 hour, until tomorrow), show it again, change the mode. The same from a URL, for example tern://hide?app=com.spotify.client&for=1h. Those links do not close windows or quit apps.