Implementing this change would be a downgrade and make this feature useless.
The purpose of the Transcendent invulnerability buff is not to wait until your character is at full HP. Its purpose is to allow you to survive the ongoing mechanics if your character was raised at the wrong moment, provided you don’t use any actions. Even if you have full HP, it doesn’t mean that mechanics can not one-shot you. Therefore if the Assist Mode resumes immediately, it may instantly kill your character once again. In certain cases, like Bozja Duels, this is extremely dangerous, because the first thing you might wish to do after being raised is to apply a Reraiser.
So no, we will not implement this change.
If you wish to discard the invulnerability buff on purpose, all you have to do is use any action of your choice and Miqobot will pick up the rotation immediately.