Ultra Instinct is a skill. To add skills, use the command “dbcskill give *skill name* and your name if you need to. You also need the godform skill to use it. Go into the action menu and enable ultra instinct. Also, since you need at least level 5 in super forms to go god, you probably need the same to go ultra instinct.
Use /jrmca set all [whatever number low enough to take damage pretty quickly]
Use /dbcspwawn [mob name] to spawn an agressive mob that’ll deal enough damage
Then go into survival mode to take the damage, fly out of their range, go UI and you’re good
If you’re on server, well ask another player to punch you to 20% or use a mob that’s strong enough.