Regarding pinning apps, you can add apps to Favorites by holding the app icon and tapping the ★ icon. On the homescreen, the pinned favorites can be shown and either sorted automatically by usage, or sorted manually to lock them in place on the screen. You can also do a mix of auto/manually sorted, so that the apps at the top are static while those below are dynamically changing.

Another option is adding one or multiple tags to each app (hold the icon, tap the three dots, then Customize). After setting some tags, you can then tap the pen icon in the bottom right corner of the Favorites view, tap the first + to add a new tag to favorites. You can then switch between "folders"/"collections" of the pinned tags inside the favorites view.