On this page
Start it
Open Shizuku.
Tap Start in the root section.
Sources: Shizuku setup guide
Start on boot
Let Shizuku run in the background with no battery limits, so it gets the start signal when the phone boots. If root mode still doesn't start on boot, rooted users can use Sui instead. KernelSU builds have been unreliable.
Sources: Shizuku setup guide, Issue 206, Issue 266
Only Start with root shows, but I'm not rooted
Then Shizuku runs in a second user or second space. Switch to the main user of the phone and open Shizuku there.
Sources: Issue 559