One Width setting for the compact and the open island: a slider in Settings › Layout, Narrow / Standard / Wide in the island's menu, or drag the island's left or right edge.
Layouts adapt instead of cutting things off: extra app icons and activities fold into +N, the Open apps grid picks its columns from the width, and the player, timer and shelf switch to compact layouts when narrow.
Dashboard columns follow the width (3, 4 or 5).
Dashboard button on the island (on hover by default; always or off in Settings).
Full-screen apps: keep showing the island, hide it unless something is live, or hide it.
Show the island on the built-in display, the display with the menu bar, or all displays.
Keyboard: <kbd>⌥⌘I</kbd> opens the dashboard (recordable in Settings), <kbd>Esc</kbd> closes it, <kbd>Tab</kbd> moves between controls.
VoiceOver descriptions and actions; an Increase Contrast edge.
Hybrid, Glass or Black material, drawn with the system's Liquid Glass so it follows your Liquid Glass slider, Reduce Transparency and Increase Contrast.
Compact style: beside the notch or below it.
Hover, click, scroll to open and close, right-click menu, alerts.
Now Playing: artwork, controls, seek; output picker (Mac outputs with a volume slider, plus Music's AirPlay speakers); synced lyrics from LRCLIB (tap a line to seek); Up Next.
Timers with presets, Battery, Calendar with meeting links, Background apps (as many as you choose).
Widget dashboard: Now Playing at most half the width, plus CPU, memory, storage and network.
Settings window with a live preview of the island, a menu bar icon, open at login, a global shortcut and dynamicisland:// links.